ORCID Profile
0000-0002-0466-1688
Current Organisation
Macquarie University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Plant Cell and Molecular Biology | Plant Physiology | Plant Biology | Agricultural Biotechnology | Proteomics and Intermolecular Interactions (excl. Medical Proteomics) | Food Processing | Agricultural Biotechnology not elsewhere classified | Bioprocessing, Bioproduction and Bioproducts | Genetically Modified Field Crops and Pasture
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Biological Sciences | Environmentally Sustainable Plant Production not elsewhere classified | Plant Production and Plant Primary Products not elsewhere classified | Barley | Aquaculture Oysters | Nutraceuticals and Functional foods |
Related Links
Publications
Response of Wheat Seedlings to Low O2Concentrations in Nutrient Solution
Publisher: Oxford University Press (OUP)
Date: 1989
DOI: 10.1093/JXB/40.9.993
Proteomic analysis of the meristematic root zone in contrasting genotypes reveals new insights in drought tolerance in rice
Publisher: Wiley
Date: 21-08-2022
Abstract: Drought is responsible for major losses in rice production. Root tips contain meristematic and elongation zones that play major roles in determination of root traits and adaptive strategies to drought. In this study we analysed two contrasting genotypes of rice: IR64, a lowland, drought‐susceptible, and shallow‐rooting genotype and Azucena, an upland, drought‐tolerant, and deep‐rooting genotype. S les were collected of root tips of plants grown under control and water deficit stress conditions. Quantitative proteomics analysis resulted in the identification of 7294 proteins from the root tips of IR64 and 6307 proteins from Azucena. Data are available via ProteomeXchange with identifier PXD033343. Using a Partial Least Square Discriminant Analysis on 4170 differentially abundant proteins, 1138 statistically significant proteins across genotypes and conditions were detected. Twenty two enriched biological processes showing contrasting patterns between two genotypes in response to stress were detected through gene ontology enrichment analysis. This included identification of novel proteins involved in root elongation with specific expression patterns in Azucena, including four Expansins and seven Class III Peroxidases. We also detected an antioxidant network and a metallo‐sulfur cluster assembly machinery in Azucena, with roles in reactive oxygen species and iron homeostasis, and positive effects on root cell cycle, growth and elongation.
The position of localized soil compaction determines root and subsequent shoot growth responses
Publisher: No publisher found
Date: 2001
DOI: 10.1093/JEXBOT/52.364.2127
Abstract: Plants growing in soils typically experience a mixture of loose and compact soil. The hypothesis that the proportion of a root system exposed to compact soil and/or the timing at which this exposure occurs determines shoot growth responses was tested. Broccoli (Brassica oleracea var. italica cv. Greenbelt) seedlings were grown in pot experiments with compact, loose and localized soil compaction created by either horizontal (compact subsoils 75 or 150 mm below loose topsoil) or vertical (adjacent compact and loose columns of soil) configurations of loose (1.2 Mg m(-3)) and compact (1.8 Mg m(-3)) soil. Entirely compact soil reduced leaf area by up to 54%, relative to loose soil. When compaction was localized, only the vertical columns of compact and loose soil reduced leaf area (by 30%). Neither the proportion of roots in compact soil nor the timing of exposure could explain the differing shoot growth responses to localized soil compaction. Instead, the strong relationship between total root length and leaf area (r(2)=0.92) indicated that localized soil compaction reduced shoot growth only when it suppressed total root length. This occurred when isolated root axes of the same plant were exposed to vertical columns of compact and loose soil. When a single root axis grew through loose soil into either a shallow or deep compact subsoil, compensatory root growth in the loose soil maintained total root length and thus shoot growth was unaffected. These contrasting root systems responses to localized soil compaction may explain the variable shoot growth responses observed under heterogeneous conditions.
Physiological responses of lupin roots to soil compaction
Publisher: Springer Science and Business Media LLC
Date: 10-1988
DOI: 10.1007/BF02139953
A Thermotolerant Variant of Rubisco Activase From a Wild Relative Improves Growth and Seed Yield in Rice Under Heat Stress
Publisher: Frontiers Media SA
Date: 20-11-2018
Nitrate and ammonium as nitrogen sources for lupins prior to nodulation
Publisher: Springer Science and Business Media LLC
Date: 1992
DOI: 10.1007/BF00009316
De novo post-illumination monoterpene burst in Quercus ilex (holm oak)
Publisher: Springer Science and Business Media LLC
Date: 18-12-2016
DOI: 10.1007/S00425-016-2636-X
Abstract: Explicit proof for de novo origin of a rare post-illumination monoterpene burst and its consistency under low O
Mechanisms of growth and patterns of gene expression in oxygen‐deprived rice coleoptiles
Publisher: Wiley
Date: 24-03-2015
DOI: 10.1111/TPJ.12786
Abstract: Coleoptiles of rice (Oryza sativa) seedlings grown under water commonly elongate by up to 1 mm h(-1) to reach the atmosphere. We initially analysed this highly specialized phenomenon by measuring epidermal cell lengths along the coleoptile axis to determine elongation rates. This revealed a cohort of cells in the basal zone that elongated rapidly following emergence from the embryo, reaching 200 μm within 12 h. After filming coleoptiles in vivo for a day, kinematic analysis was applied. Eight time-sliced 'segments' were defined by their emergence from the embryo at four-hourly intervals, revealing a mathematically simple growth model. Each segment entering the coleoptile from the embryo elongated at a constant velocity, resulting in accelerating growth for the entire organ. Consistent with the epidermal cell lengths, relative rates of elongation (mm mm(-1) h(-1)) were tenfold greater in the small, newly emerged basal segments than the older distal tip segments. This steep axial gradient defined two contrasting growth zones (bases versus tips) in which we measured ATP production and protein, RNA and DNA content, and analysed the global transcriptome under steady-state normoxia, hypoxia (3% O2) and anoxia. Determination of the transcriptome revealed tip-specific induction of genes encoding TCP [Teosinte Branched1 (Tb1) of maize, Cycloidea (Cyc), and Proliferating Cell Factor (Pcf)] transcription factors, RNA helicases, ribosomal proteins and proteins involved in protein folding, whilst expression of F-box domain-containing proteins in the ubiquitin E3-SCF complex (Skp, Cullin, F-box containing complex) was induced specifically in bases under low oxygen conditions. We ascribed the sustained elongation under hypoxia to hypoxia-specific responses such as controlled suppression of photosystem components and induction of RNA binding/splicing functions, indicating preferential allocation of energy to cell extension.
Optimal Silver Nitrate Concentration to Inhibit α‐Amylase Activity During Pasting of Rice Flour
Publisher: Wiley
Date: 06-11-2020
Does soil nitrogen influence growth, water transport and survival of snow gum (Eucalyptus pauciflora Sieber ex Sprengel.) under CO2 enrichment?
Publisher: Wiley
Date: 05-2009
DOI: 10.1111/J.1365-3040.2009.01949.X
Abstract: Eucalyptus pauciflora Sieber ex Sprengel. (snow gum) was grown under ambient (370 microL L(-1)) and elevated (700 microL L(-1)) atmospheric [CO2] in open-top chambers (OTCs) in the field and temperature-controlled glasshouses. Nitrogen applications to the soil ranged from 0.1 to 2.75 g N per plant. Trees in the field at high N levels grew rapidly during summer, particularly in CO2-enriched atmosphere, but suffered high mortality during summer heatwaves. Generally, wider and more numerous secondary xylem vessels at the root-shoot junction in CO2-enriched trees conferred fourfold higher below-ground hydraulic conductance. Enhanced hydraulic capacity was typical of plants at elevated [CO2] (in which root and shoot growth was accelerated), but did not result from high N supply. However, because high rates of N application consistently made trees prone to dehydration during heatwaves, glasshouse studies were required to identify the effect of N nutrition on root development and hydraulics. While the effects of elevated [CO2] were again predominantly on hydraulic conductivity, N nutrition acted specifically by constraining deep root penetration into soil. Specifically, 15-40% shallower root systems supported marginally larger shoot canopies. Independent changes to hydraulics and root penetration have implications for survival of fertilized trees under elevated atmospheric [CO2], particularly during water stress.
Consequences of waterlogging in cotton and opportunities for mitigation of yield losses
Publisher: Oxford University Press (OUP)
Date: 2015
Species-specific photorespiratory rate, drought tolerance and isoprene emission rate in plants
Publisher: Informa UK Limited
Date: 03-03-2015
Growth rate and phosphate utilization of some Carex species from a range of oligotrophic to eutrophic swamp habitats
Publisher: Wiley
Date: 11-1980
Wild and Cultivated Species of Rice Have Distinctive Proteomic Responses to Drought
Publisher: MDPI AG
Date: 19-08-2020
DOI: 10.3390/IJMS21175980
Abstract: Drought often compromises yield in non-irrigated crops such as rainfed rice, imperiling the communities that depend upon it as a primary food source. In this study, two cultivated species (Oryza sativa cv. Nipponbare and Oryza glaberrima cv. CG14) and an endemic, perennial Australian wild species (Oryza australiensis) were grown in soil at 40% field capacity for 7 d (drought). The hypothesis was that the natural tolerance of O. australiensis to erratic water supply would be reflected in a unique proteomic profile. Leaves from droughted plants and well-watered controls were harvested for label-free quantitative shotgun proteomics. Physiological and gene ontology analysis confirmed that O. australiensis responded uniquely to drought, with superior leaf water status and enhanced levels of photosynthetic proteins. Distinctive patterns of protein accumulation in drought were observed across the O. australiensis proteome. Photosynthetic and stress-response proteins were more abundant in drought-affected O. glaberrima than O. sativa, and were further enriched in O. australiensis. In contrast, the level of accumulation of photosynthetic proteins decreased when O. sativa underwent drought, while a narrower range of stress-responsive proteins showed increased levels of accumulation. Distinctive proteomic profiles and the accumulated levels of in idual proteins with specific functions in response to drought in O. australiensis indicate the importance of this species as a source of stress tolerance genes.
The effect of soil compaction on wheat during early tillering
Publisher: Wiley
Date: 05-1990
Anatomical variation in juvenile eucalypt leaves accounts for differences in specific leaf area and CO2 assimilation rates
Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/BT01059
Abstract: Specific leaf area (SLA) is an important leaf attribute representing a compromise between the capture of light and CO2 and the limitations imposed by leaf structure, herbivore resistance and the mitigation of water loss. We examined three Eucalyptus L'Her. species to determine whether variation in CO2 assimilation rate was related to SLA and leaf anatomy. Seedlings were grown in a naturally illuminated glasshouse with adequate water and nutrients. Light-saturated rates of photosynthesis were measured on the youngest fully expanded leaves. Mesophyll characteristics were measured from sections thick of the interveinal leaf lamina. Significant interspecies variation in SLA corresponded to clear trends in anatomy and photosynthesis. Low-SLA leaves were thicker, having increased thickness of palisade mesophyll because of a greater number of palisade layers. E. occidentalis, E.camaldulensis and E. grandis had 3.7, 2.0 and 1.0 layers of palisade cells which corresponded to an SLA of 14.8, 17.6 and 21.8 m2 kg-1, respectively. High investment of dry mass in photosynthetic tissue was associated with higher leaf N (area and mass) concentration, chlorophyll concentration and photosynthetic capacity per leaf area. Leaf morphology affected use of the resources N, water and CO2. In contrast to the thin leaves of E. grandis, thick leaves of E. occidentalis had low N-use efficiency and high instantaneous water-use efficiency. Differences in leaf structure of these species appear to reflect the most limiting resource experienced in the environments to which they have adapted.
Patterns of gene expression in pollen of cotton (Gossypium hirsutum) indicate down-regulation as a feature of thermotolerance
Publisher: Cold Spring Harbor Laboratory
Date: 07-06-2021
DOI: 10.1101/2021.06.06.447035
Abstract: Reproductive performance in plants is impaired as maximum temperatures consistently approach 40°C. However, the timing of heatwaves critically affects their impact. We studied the molecular responses of cotton male reproductive stages, to investigate the vulnerability of maturing pollen to high temperature. Tetrads, uninucleate and binucleate microspores, and mature pollen were subjected to SWATH-MS and RNA-seq analyses after exposure to 38/28°C (day/night) for 5 days. The results indicated that molecular signatures were down-regulated over developmental stages in response to heat. This was more evident in leaves where three-quarters of differentially changed proteins were decreased in abundance. Functional analysis showed that translation of genes increased in tetrads after exposure to heat however, the reverse pattern was observed in mature pollen and leaves. Proteins involved in transport were highly abundant in tetrads, whereas in later stages of development and leaves, heat suppressed cell-to-cell communication. Moreover, a large number of heat shock proteins (HSPs) were identified in heat-affected tetrads, but these proteins were less abundant in mature pollen and leaves. We speculate that the sensitivity of tetrad cells to heat is related to increased activity of translation involved in non-essential pathways. Molecular signatures during pollen development after heatwaves provide markers for future genetic improvement.
Carbohydrate Metabolism of Rice Seedlings Grown in Oxygen Deficient Solution
Publisher: Oxford University Press (OUP)
Date: 1987
DOI: 10.1093/JXB/38.3.466
Multiple Abiotic Stresses Applied Simultaneously Elicit Distinct Responses in Two Contrasting Rice Cultivars
Publisher: MDPI AG
Date: 03-02-2022
DOI: 10.3390/IJMS23031739
Abstract: Rice crops are often subject to multiple abiotic stresses simultaneously in both natural and cultivated environments, resulting in yield reductions beyond those expected from single stress. We report physiological changes after a 4 day exposure to combined drought, salt and extreme temperature treatments, following a 2 day salinity pre-treatment in two rice genotypes—Nipponbare (a paddy rice) and IAC1131 (an upland landrace). Stomata closed after two days of combined stresses, causing intercellular CO2 concentrations and assimilation rates to diminish rapidly. Abscisic acid (ABA) levels increased at least five-fold but did not differ significantly between the genotypes. Tandem Mass Tag isotopic labelling quantitative proteomics revealed 6215 reproducibly identified proteins in mature leaves across the two genotypes and three time points (0, 2 and 4 days of stress). Of these, 987 were differentially expressed due to stress (cf. control plants), including 41 proteins that changed significantly in abundance in all stressed plants. Heat shock proteins, late embryogenesis abundant proteins and photosynthesis-related proteins were consistently responsive to stress in both Nipponbare and IAC1131. Remarkably, even after 2 days of stress there were almost six times fewer proteins differentially expressed in IAC1131 than Nipponbare. This contrast in the translational response to multiple stresses is consistent with the known tolerance of IAC1131 to dryland conditions.
Heat tolerance in a wild Oryza species is attributed to maintenance of Rubisco activation by a thermally stable Rubisco activase ortholog
Publisher: Wiley
Date: 05-05-2016
DOI: 10.1111/NPH.13963
Abstract: The mechanistic basis of tolerance to heat stress was investigated in Oryza sativa and two wild rice species, Oryza meridionalis and Oryza australiensis . The wild relatives are endemic to the hot, arid Australian savannah. Leaf elongation rates and gas exchange were measured during short periods of supra‐optimal heat, revealing species differences. The Rubisco activase ( RCA ) gene from each species was sequenced. Using expressed recombinant RCA and leaf‐extracted RCA , the kinetic properties of the two isoforms were studied under high temperatures. Leaf elongation was undiminished at 45°C in O . australiensis . The net photosynthetic rate was almost 50% slower in O . sativa at 45°C than at 28°C, while in O . australiensis it was unaffected. Oryza meridionalis exhibited intermediate heat tolerance. Based on previous reports that RCA is heat‐labile, the Rubisco activation state was measured. It correlated positively with leaf elongation rates across all three species and four periods of exposure to 45°C. Sequence analysis revealed numerous polymorphisms in the RCA amino acid sequence from O . australiensis . The O. australiensis RCA enzyme was thermally stable up to 42°C, contrasting with RCA from O. sativa , which was inhibited at 36°C. We attribute heat tolerance in the wild species to thermal stability of RCA , enabling Rubisco to remain active.
The Effect of Oxygen and Turbulence on Elongation of Coleoptiles of Submergence-Tolerant and -Intolerant Rice Cultivars
Publisher: Oxford University Press (OUP)
Date: 1982
Elevated CO2 differentially affects the properties of grain from wild and domesticated rice
Publisher: Elsevier BV
Date: 07-2021
The extracellular matrix of plants: Molecular, cellular and developmental biology
Publisher: Wiley
Date: 09-01-1993
Reduced Susceptibility of Roots of Safflower to Phytophthora cryptogea After Prior Adaptation of Roots to Hypoxic Conditions
Publisher: CSIRO Publishing
Date: 1994
DOI: 10.1071/BT9940029
Abstract: Safflower (Carthamus tinctorius L. cv. Gila) was grown in solution culture the roots were inoculated with zoospores of Phytophthora cryptogea 28 d after sowing. The period for which roots were subjected to hypoxia prior to inoculation (5%(v/v) O2 in the gas stream) had a profound influence on the degree of hyphal damage to roots 8 d after inoculation. Roots exposed to hypoxia for 7 d prior to inoculation were not more than 20% necrotic 8 d after inoculation and the shoots were fully hydrated, presumably through sustained water transport by the root. Plants which were exposed to hypoxia for just 1 d after inoculation, on the other hand, developed almost total necrosis of the root system and the shoots wilted severely subsequent to infection. We propose that while short periods of hypoxia pre-dispose safflower roots to hyphal infection, a longer period of adaptation to hypoxia reverses this susceptibility. The mechanism for this protective effect, while not known, could reside in root aerenchyma formation, phytoalexin synthesis, or other metabolic and ultrastructual changes characteristic of roots exposed to low O2 conditions.
Low Incident Light Combined with Partial Waterlogging Impairs Photosynthesis and Imposes a Yield Penalty in Cotton
Publisher: Wiley
Date: 28-01-2016
DOI: 10.1111/JAC.12164
Impact of elevated atmospheric CO2 on aleurone cells and starch granule morphology in domesticated and wild rices
Publisher: Elsevier BV
Date: 2022
Turgor-dependent efflux of assimilates from coats of developing seed of Phaseolus vulgaris L.: water relations of the cells involved in efflux
Publisher: Springer Science and Business Media LLC
Date: 05-1996
DOI: 10.1007/BF00196877
Patterns of gene expression in pollen of cotton (Gossypium hirsutum) indicate downregulation as a feature of thermotolerance
Publisher: Wiley
Date: 17-12-2021
DOI: 10.1111/TPJ.15608
Abstract: Reproductive performance in plants is impaired as maximum temperatures consistently approach 40°C. However, the timing of heatwaves critically affects their impact. We studied the molecular responses during pollen maturation in cotton to investigate the vulnerability to high temperature. Tetrads (TEs), uninucleate and binucleate microspores, and mature pollen were subjected to SWATH‐MS and RNA‐seq analyses after exposure to 38/28°C (day/night) for 5 days. The results indicated that molecular signatures were downregulated progressively in response to heat during pollen development. This was even more evident in leaves, where three‐quarters of differentially changed proteins decreased in abundance during heat. Functional analysis showed that translation of genes increased in TEs after exposure to heat however, the reverse pattern was observed in mature pollen and leaves. For ex le, proteins involved in transport were highly abundant in TEs whereas in later stages of pollen formation and leaves, heat suppressed synthesis of proteins involved in cell‐to‐cell communication. Moreover, a large number of heat shock proteins were identified in heat‐affected TEs, but these proteins were less abundant in mature pollen and leaves. We speculate that the sensitivity of TE cells to heat is related to high rates of translation targeted to pathways that might not be essential for thermotolerance. Molecular signatures during stages of pollen development after heatwaves could provide markers for future genetic improvement.
Evolution of isoprene emission capacity in plants
Publisher: Elsevier BV
Date: 07-2014
DOI: 10.1016/J.TPLANTS.2014.01.009
Abstract: Light-dependent de novo volatile isoprene emission by terrestrial plants (approximately 2% of carbon fixed during photosynthesis) contributes as much as 0.5 PgC/year to the global carbon cycle. Although most plant taxa exhibit either constitutive or inducible monoterpene emissions, the evolution of isoprene emission capacity in multiple lineages has remained unexplained. Based on the predominant occurrence of isoprene emission capacity in long-lived, fast-growing woody plants the relationship between 'metabolic scope' of tree genera and their species richness and the proposed role of high growth rates and long generation times in accelerating molecular evolution, we hypothesise that long-lived plant genera with inherently high speciation rates have repeatedly acquired and lost the capacity to emit isoprene in their evolutionary history.
The influence of oxygen deficiency on ethylene synthesis, 1‐aminocyclopropane‐1‐carboxylic acid levels and aerenchyma formation in roots of Zea mays
Publisher: Wiley
Date: 1988
Pre-Treatment of Rice Plants with ABA Makes Them More Tolerant to Multiple Abiotic Stress
Publisher: MDPI AG
Date: 06-2023
DOI: 10.3390/IJMS24119628
Abstract: Multiple abiotic stress is known as a type of environmental unfavourable condition maximizing the yield and growth gap of crops compared with the optimal condition in both natural and cultivated environments. Rice is the world’s most important staple food, and its production is limited the most by environmental unfavourable conditions. In this study, we investigated the pre-treatment of abscisic acid (ABA) on the tolerance of the IAC1131 rice genotype to multiple abiotic stress after a 4-day exposure to combined drought, salt and extreme temperature treatments. A total of 3285 proteins were identified and quantified across the four treatment groups, consisting of control and stressed plants with and without pre-treatment with ABA, with 1633 of those proteins found to be differentially abundant between groups. Compared with the control condition, pre-treatment with the ABA hormone significantly mitigated the leaf damage against combined abiotic stress at the proteome level. Furthermore, the application of exogenous ABA did not affect the proteome profile of the control plants remarkably, while the results were different in stress-exposed plants by a greater number of proteins changed in abundance, especially those which were increased. Taken together, these results suggest that exogenous ABA has a potential priming effect for enhancing the rice seedlings’ tolerance against combined abiotic stress, mainly by affecting stress-responsive mechanisms dependent on ABA signalling pathways in plants.
The fate of carbon and fertiliser nitrogen when dryland wheat is grown in monoliths of duplex soil
Publisher: Springer Science and Business Media LLC
Date: 2002
Label-free and isobaric tandem mass tag (TMT) multiplexed quantitative proteomic data of two contrasting rice cultivars exposed to drought stress and recovery
Publisher: Elsevier BV
Date: 02-2019
Physiological Mechanisms of Flooding Tolerance in Rice: Transient Complete Submergence and Prolonged Standing Water
Publisher: Springer Berlin Heidelberg
Date: 07-2013
Adaptation of Rice to Flooded Soils
Publisher: Springer Berlin Heidelberg
Date: 07-2013
Strategic Distribution of Protective Proteins within Bran Layers of Wheat Protects the Nutrient-Rich Endosperm
Publisher: Oxford University Press (OUP)
Date: 08-01-2010
Abstract: Bran from bread wheat (Triticum aestivum ‘Babbler’) grain is composed of many outer layers of dead maternal tissues that overlie living aleurone cells. The dead cell layers function as a barrier resistant to degradation, whereas the aleurone layer is involved in mobilizing organic substrates in the endosperm during germination. We microdissected three defined bran fractions, outer layers (epidermis and hypodermis), intermediate fraction (cross cells, tube cells, testa, and nucellar tissue), and inner layer (aleurone cells), and used proteomics to identify their in idual protein complements. All proteins of the outer layers were enzymes, whose function is to provide direct protection against pathogens or improve tissue strength. The more complex proteome of the intermediate layers suggests a greater ersity of function, including the inhibition of enzymes secreted by pathogens. The inner layer contains proteins involved in metabolism, as would be expected from live aleurone cells, but this layer also includes defense enzymes and inhibitors as well as 7S globulin (specific to this layer). Using immunofluorescence microscopy, oxalate oxidase was localized predominantly to the outer layers, xylanase inhibitor protein I to the xylan-rich nucellar layer of the intermediate fraction and pathogenesis-related protein 4 mainly to the aleurone. Activities of the water-extractable enzymes oxalate oxidase, peroxidase, and polyphenol oxidase were highest in the outer layers, whereas chitinase activity was found only in assays of whole grains. We conclude that the differential protein complements of each bran layer in wheat provide distinct lines of defense in protecting the embryo and nutrient-rich endosperm.
Endogenous Ethylene Concentration Is Not a Major Determinant of Fruit Abscission in Heat-Stressed Cotton (Gossypium hirsutum L.)
Publisher: Frontiers Media SA
Date: 21-09-2017
Efficient use of energy in anoxia‐tolerant plants with focus on germinating rice seedlings
Publisher: Wiley
Date: 04-12-2014
DOI: 10.1111/NPH.13173
Abstract: Anoxia tolerance in plants is distinguished by direction of the sparse supply of energy to processes crucial to cell maintenance and sometimes to growth, as in rice seedlings. In anoxic rice coleoptiles energy is used to synthesise proteins, take up K + , synthesise cell walls and lipids, and in cell maintenance. Maintenance of electrochemical H + gradients across the tonoplast and plasma membrane is crucial for solute compartmentation and thus survival. These gradients sustain some H + ‐solute cotransport and regulate cytoplasmic pH . Pyrophosphate (PP i ), the alternative energy donor to ATP , allows direction of energy to the vacuolar H + ‐PP i ase, sustaining H + gradients across the tonoplast. When energy production is critically low, operation of a biochemical pH stat allows H + ‐solute cotransport across plasma membranes to continue for at least for 18 h. In active (e.g. growing) cells, PP i produced during substantial polymer synthesis allows conversion of PP i to ATP by PP i ‐phosphofructokinase (PFK). In quiescent cells with little polymer synthesis and associated PP i formation, the PP i required by the vacuolar H + ‐PP i ase and UDPG pyrophosphorylase involved in sucrose mobilisation via sucrose synthase might be produced by conversion of ATP to PP i through reversible glycolytic enzymes, presumably pyruvate orthophosphate dikinase. These hypotheses need testing with species characterised by contrasting anoxia tolerance. Contents Summary 36 I. Introduction 36 II. PP i ‐dependent enzymes as a key adaptation to an energy crisis, enabling survival and growth in anoxia 37 III. Mechanisms of survival during an energy crisis: that is, plant quiescence during anoxia with no growth and acclimated cells in anoxia 44 IV. Energy expenditure during growth under anoxia 49 V. Conclusions on mechanisms of anoxia tolerance 53 Acknowledgements 54 References 55
Increased Ratio of Electron Transport to Net Assimilation Rate Supports Elevated Isoprenoid Emission Rate in Eucalypts under Drought
Publisher: Oxford University Press (OUP)
Date: 19-08-2014
Abstract: Plants undergoing heat and low-CO2 stresses emit large amounts of volatile isoprenoids compared with those in stress-free conditions. One hypothesis posits that the balance between reducing power availability and its use in carbon assimilation determines constitutive isoprenoid emission rates in plants and potentially even their maximum emission capacity under brief periods of stress. To test this, we used abiotic stresses to manipulate the availability of reducing power. Specifically, we examined the effects of mild to severe drought on photosynthetic electron transport rate (ETR) and net carbon assimilation rate (NAR) and the relationship between estimated energy pools and constitutive volatile isoprenoid emission rates in two species of eucalypts: Eucalyptus occidentalis (drought tolerant) and Eucalyptus camaldulensis (drought sensitive). Isoprenoid emission rates were insensitive to mild drought, and the rates increased when the decline in NAR reached a certain species-specific threshold. ETR was sustained under drought and the ETR-NAR ratio increased, driving constitutive isoprenoid emission until severe drought caused carbon limitation of the methylerythritol phosphate pathway. The estimated residual reducing power unused for carbon assimilation, based on the energetic status model, significantly correlated with constitutive isoprenoid emission rates across gradients of drought (r 2 & 0.8) and photorespiratory stress (r 2 & 0.9). Carbon availability could critically limit emission rates under severe drought and photorespiratory stresses. Under most instances of moderate abiotic stress levels, increased isoprenoid emission rates compete with photorespiration for the residual reducing power not invested in carbon assimilation. A similar mechanism also explains the in idual positive effects of low-CO2, heat, and drought stresses on isoprenoid emission.
Factors which affects the growth of grain legumes on a solonized brown soil. I. Genotypic responses to soil physical factors
Publisher: CSIRO Publishing
Date: 1991
DOI: 10.1071/AR9910095
Abstract: Lupins (Lupinus angustifolius cvv. Yandee and 75A-258 and L. pilosus cv. P. 20957) and pea (Pisum sativum cv. Dundale) were grown in the field for 43 days on a solonized brown soil. Shoots of L. pilosus and peas grew most rapidly, while L. angustifolius cv. 75A-258 developed a relatively large root system. L. angustifolius cv. Yandee, a commercial lupin cultivar, was poorly adapted shoot growth was restricted and roots ceased growing 36 days after sowing. The soil factors responsible for these widely differing responses were investigated. Once primary roots of L. angustifolius were 20-30 cm deep, root extension was slow or arrested. Indeed, primary root apices of Yandee were often necrotic in the soil below 20 cm. In contrast, roots proliferated rapidly in the surface 20 cm of the soil, particularly in 7SA-258, suggesting that factors in the deeper soil layers restricted root growth most severely. The vigorous growth of lateral roots of 75A-258 was reflected in a 2.6 fold greater total root length than for Yandee 43 days after sowing. Soil physical properties were not considered a likely explanation for these observations soil water status and porosity were always favourable for root growth and root sections indicated that no cortical degradation, typical of O2 deficient roots, had occurred. Penetrometer resistance and root tip osmotic pressures suggested that poor root growth could not be ascribed simply to soil mechanical properties. The results suggest, by inference, that soil chemical factors could underlie the phenotypic responses observed.
The Relationship Between Growth and Oxygen Uptake in Hypoxic Rice Seedlings
Publisher: Oxford University Press (OUP)
Date: 1987
DOI: 10.1093/JXB/38.3.454
The fate of carbon in pulse-labelled crops of barley and wheat
Publisher: Springer Science and Business Media LLC
Date: 10-1991
DOI: 10.1007/BF02150051
Response of Wheat Seedlings to Low O2Concentrations in Nutrient Solution
Publisher: Oxford University Press (OUP)
Date: 1989
DOI: 10.1093/JXB/40.9.985
Response of roots to mechanical impedance
Publisher: Elsevier BV
Date: 1993
Serpins in rice: protein sequence analysis, phylogeny and gene expression during development
Publisher: Springer Science and Business Media LLC
Date: 04-09-2012
Abstract: Most members of the serpin family of proteins are potent, irreversible inhibitors of specific serine or cysteine proteinases. Inhibitory serpins are distinguished from members of other families of proteinase inhibitors by their metastable structure and unique suicide-substrate mechanism. Animal serpins exert control over a remarkable ersity of physiological processes including blood coagulation, fibrinolysis, innate immunity and aspects of development. Relatively little is known about the complement of serpin genes in plant genomes and the biological functions of plant serpins. A structurally refined amino-acid sequence alignment of the 14 full-length serpins encoded in the genome of the japonica rice Oryza sativa cv. Nipponbare (a monocot) showed a ersity of reactive-centre sequences (which largely determine inhibitory specificity) and a low degree of identity with those of serpins in Arabidopsis (a eudicot). A new convenient and functionally informative nomenclature for plant serpins in which the reactive-centre sequence is incorporated into the serpin name was developed and applied to the rice serpins. A phylogenetic analysis of the rice serpins provided evidence for two main clades and a number of relatively recent gene duplications. Transcriptional analysis showed vastly different levels of basal expression among eight selected rice serpin genes in callus tissue, during seedling development, among vegetative tissues of mature plants and throughout seed development. The gene OsSRP-LRS (Os03g41419), encoding a putative orthologue of Arabidopsis AtSerpin1 (At1g47710), was expressed ubiquitously and at high levels. The second most highly expressed serpin gene was OsSRP-PLP (Os11g11500), encoding a non-inhibitory serpin with a surprisingly well-conserved reactive-centre loop (RCL) sequence among putative orthologues in other grass species. The ersity of reactive-centre sequences among the putatively inhibitory serpins of rice point to a range of target proteases with different proteolytic specificities. Large differences in basal expression levels of the eight selected rice serpin genes during development further suggest a range of functions in regulation and in plant defence for the corresponding proteins.
Pollen development in cotton (Gossypium hirsutum) is highly sensitive to heat exposure during the tetrad stage
Publisher: Wiley
Date: 03-11-2020
DOI: 10.1111/PCE.13908
Abstract: The development of gametes in plants is acutely susceptible to heatwaves as brief as a few days, adversely affecting pollen maturation and reproductive success. Pollen in cotton ( Gossypium hirsutum ) was differentially affected when tetrad and binucleate stages were exposed to heat, revealing new insights into the interaction between heat and pollen development. Squares were tagged and exposed to 36/25°C (day/night, moderate heat) or 40/30°C (day/night, extreme heat) for 5 days. Mature pollen grains and leaves were collected for physiological and proteomic responses. While photosynthetic competence was not compromised even at 40°C, leaf tissues became leakier. In contrast, pollen grains were markedly smaller after the tetrad stage was exposed to 40°C and boll production was reduced by 65%. Sugar levels in pollen grains were elevated after exposure to heat, eliminating carbohydrate deficits as a likely cause of poor reproductive capacity. Proteomic analysis of pure pollen s les revealed a particularly high abundance of 70‐kDa heat shock (Hsp70s) and cytoskeletal proteins. While short‐term bursts of heat had a minor impact on leaves, male gametophyte development was profoundly damaged. Cotton acclimates to maxima of 36°C at both the vegetative and reproductive stages but 5‐days exposure to 40°C significantly impairs reproductive development.
Differential regulation of aquaporins, small GTP ases and V ‐ATP ases proteins in rice leaves subjected to drought stress and recovery
Publisher: Wiley
Date: 03-2012
Abstract: Mechanisms of drought tolerance are complex, interacting, and polygenic. This paper describes patterns of gene expression at precise physiological stages of drought in 35-day-old seedlings of Oryza sativa cv. Nipponbare. Drought was imposed gradually for up to 15 days, causing abscisic acid levels to rise and growth to cease, and plants were then re-watered. Proteins were identified from leaf s les after moderate drought, extreme drought, and 3 and 6 days of re-watering. Label-free quantitative shotgun proteomics resulted in identification of 1548 non-redundant proteins. More proteins were down-regulated in early stages of drought but more were up-regulated as severe drought developed. After re-watering, there was notable down regulation, suggesting that stress-related proteins were being degraded. Proteins involved in signalling and transport became dominant as severe drought took hold but decreased again on re-watering. Most of the nine aquaporins identified were responsive to drought, with six decreasing rapidly in abundance as plants were re-watered. Nine G-proteins appeared in large amounts during severe drought and dramatically degraded once plants were re-watered. We speculate that water transport and drought signalling are critical elements of the overall response to drought in rice and might be the key to biotechnological approaches to drought tolerance.
Proteomic Responses to Drought Vary Widely Among Eight Diverse Genotypes of Rice (Oryza sativa)
Publisher: MDPI AG
Date: 06-01-2020
DOI: 10.3390/IJMS21010363
Abstract: Rice is a critically important food source but yields worldwide are vulnerable to periods of drought. We exposed eight genotypes of upland and lowland rice (Oryza sativa L. ssp. japonica and indica) to drought stress at the late vegetative stage, and harvested leaves for label-free shotgun proteomics. Gene ontology analysis was used to identify common drought-responsive proteins in vegetative tissues, and leaf proteins that are unique to in idual genotypes, suggesting ersity in the metabolic responses to drought. Eight proteins were found to be induced in response to drought stress in all eight genotypes. A total of 213 proteins were identified in a single genotype, 83 of which were increased in abundance in response to drought stress. In total, 10 of these 83 proteins were of a largely uncharacterized function, making them candidates for functional analysis and potential biomarkers for drought tolerance.
Differential proteomic response of rice (Oryza sativa) leaves exposed to high‐ and low‐temperature stress
Publisher: Wiley
Date: 22-06-2011
Abstract: Global mean surface temperature has been predicted to increase by 1.8-4°C within this century, accompanied by an increase in the magnitude and frequency of extreme temperature events. Developing rice cultivars better adapted to non-optimal temperatures is essential to increase rice yield in the future and, hence, understanding the molecular response of rice to temperature stress is necessary. In this study, we investigated the proteomic responses of leaves of 24-day-old rice seedlings to sudden temperature changes. Rice seedlings grown at 28/20°C (day/night) were subjected to 3-day exposure to 12/5°C or 20/12°C (day/night) for low-temperature stress, and 36/28°C or 44/36°C (day/night) for high-temperature stress, followed by quantitative label-free shotgun proteomic analysis on biological triplicates of each treatment. Out of over 1100 proteins identified in one or more temperature treatments, more than 400 were found to be responsive to temperature stress. Of these, 43, 126 and 47 proteins were exclusively found at 12/5, 20/12 and 44/36°C (day/night), respectively. Our results showed that a greater change occurs in the rice leaf proteome at 20/12°C (day/night) in comparison to other non-optimal temperature regimes. In addition, our study identified more than 20 novel stress-response proteins.
Serpin genes AtSRP2 and AtSRP3 are required for normal growth sensitivity to a DNA alkylating agent in Arabidopsis
Publisher: Springer Science and Business Media LLC
Date: 11-05-2009
Abstract: The complex responses of plants to DNA damage are incompletely understood and the role of members of the serpin protein family has not been investigated. Serpins are functionally erse but structurally conserved proteins found in all three domains of life. In animals, most serpins have regulatory functions through potent, irreversible inhibition of specific serine or cysteine proteinases via a unique suicide-substrate mechanism. Plant serpins are also potent proteinase inhibitors, but their physiological roles are largely unknown. Six Arabidopsis genes encoding full-length serpins were differentially expressed in developing seedlings and mature tissues. Basal levels of AtSRP2 (At2g14540) and AtSRP3 (At1g64030) transcripts were highest in reproductive tissues. AtSRP2 was induced 5-fold and AtSRP3 100-fold after exposure of seedlings to low concentrations of methyl methanesulfonate (MMS), a model alkylating reagent that causes DNA damage. Homozygous T-DNA insertion mutants atsrp2 and atsrp3 exhibited no differential growth when mutant and wild-type plants were left untreated or exposed to γ-radiation or ultraviolet light. In contrast, atsrp2 and atsrp3 plants exhibited greater root length, leaf number and overall size than wild-type plants when exposed to MMS. Neither of the two serpins was required for meiosis. GFP-AtSRP2 was localized to the nucleus, whereas GFP-AtSRP3 was cytosolic, suggesting that they target different proteinases. Induction of cell cycle- and DNA damage-related genes AtBRCA1 , AtBARD1 , AtRAD51 , AtCYCB1 and AtCYCD1 , but not AtATM , was reduced relative to wild-type in atsrp2 and atsrp3 mutants exposed to MMS. Expression of specific serpin genes ( AtSRP2 and AtSRP3 in Arabidopsis ) is required for normal responses of plants following exposure to alkylating genotoxins such as MMS.
Cellulose-binding modules from extracellular matrix proteins ofDictyostelium discoideumstalk and sheath
Publisher: Wiley
Date: 08-2001
DOI: 10.1046/J.1432-1327.2001.02354.X
Abstract: Cellulose-binding modules (CBMs) of two extracellular matrix proteins, St15 and ShD, from the slime mold Dictyostelium discoideum were expressed in Escherichia coli. The expressed proteins were purified to > 98% purity by extracting inclusion bodies at pH 11.5 and refolding proteins at pH 7.5. The two refolded CBMs bound tightly to amorphous phosphoric acid swollen cellulose (PASC), but had a low affinity toward xylan. Neither protein exhibited cellulase activity. St15, the stalk-specific protein, had fourfold higher binding affinity toward microcrystalline cellulose (Avicel) than the sheath-specific ShD CBM. St15 is unusual in that it consists of a solitary CBM homologous to family IIa CBMs. Sequence analysis of ShD reveals three putative domains containing: (a) a C-terminal CBM homologous to family IIb CBMs (b) a Pro/Thr-rich linker domain and (c) a N-terminal Cys-rich domain. The biological functions and potential role of St15 and ShD in building extracellular matrices during D. discoideum development are discussed.
Proteomes of Leaf‐Growing Zones in Rice Genotypes with Contrasting Drought Tolerance
Publisher: Wiley
Date: 18-04-2019
Abstract: Plants require a distinctive cohort of enzymes to coordinate cell ision and expansion. Proteomic analysis now enables interrogation of immature leaf bases where these processes occur. Hence, proteins in tissues s led from leaves of a drought-tolerant rice (IAC1131) are investigated to provide insights into the effect of soil drying on gene expression relative to the drought-sensitive genotype Nipponbare. Shoot growth zones are dissected to estimate the proportion of iding cells and extract protein for subsequent tandem mass tags quantitative proteomic analysis. Gene ontology annotations of differentially expressed proteins provide insights into responses of Nipponbare and IAC1131 to drought. Soil drying does not affect the percentage of mitotic cells in IAC1131. More than 800 proteins across most functional categories increase in drought (and decrease on rewatering) in IAC1131, including proteins involved in "organizing the meristem" and "new cell formation". On the other hand, the percentage of iding cells in Nipponbare is severely impaired during drought and fewer than 200 proteins respond in abundance when growing zones undergo a drying cycle. Remarkably, the proteomes of the growing zones of each genotype respond in a highly distinctive manner, reflecting their contrasting drought tolerance even at the earliest stages of leaf development.
Community recommendations on terminology and procedures used in flooding and low oxygen stress research
Publisher: Wiley
Date: 09-03-2017
DOI: 10.1111/NPH.14519
Could abiotic stress tolerance in wild relatives of rice be used to improve Oryza sativa?
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.PLANTSCI.2013.10.007
Abstract: Oryza sativa and Oryza glaberrima have been selected to acquire and partition resources efficiently as part of the process of domestication. However, genetic ersity in cultivated rice is limited compared to wild Oryza species, in spite of 120,000 genotypes being held in gene banks. By contrast, there is untapped ersity in the more than 20 wild species of Oryza, some having been collected from just a few coastal locations (e.g. Oryza schlechteri), while others are widely distributed (e.g. Oryza nivara and Oryza rufipogon). The extent of DNA sequence ersity and phenotypic variation is still being established in wild Oryza, with genetic barriers suggesting a vast range of morphologies and function even within species, such as has been demonstrated for Oryza meridionalis. With increasing climate variability and attempts to make more marginal land arable, abiotic and biotic stresses will be managed over the coming decades by tapping into the genetic ersity of wild relatives of O. sativa. To help create a more targeted approach to sourcing wild rice germplasm for abiotic stress tolerance, we have created a climate distribution map by plotting the natural occurrence of all Oryza species against corresponding temperature and moisture data. We then discuss interspecific variation in phenotype and its significance for rice, followed by a discussion of ways to integrate germplasm from wild relatives into domesticated rice.
Quantifying ATP turnover in anoxic coleoptiles of rice (Oryza sativa) demonstrates preferential allocation of energy to protein synthesis
Publisher: Oxford University Press (OUP)
Date: 13-05-2012
DOI: 10.1093/JXB/ERS114
The effect of soil compaction on wheat during early tillering
Publisher: Wiley
Date: 05-1990
The effect of co-occurring heat and water stress on reproductive traits and yield of tomato (Solanum lycopersicum)
Publisher: Japanese Society for Horticultural Science
Date: 2020
Canopy development and hydraulic function in Eucalyptus tereticornis grown in drought in CO2-enriched atmospheres
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/FP06338
Abstract: We report on the relationship between growth, partitioning of shoot biomass and hydraulic development of Eucalyptus tereticornis Sm. grown in glasshouses for six months. Close coordination of stem vascular capacity and shoot architecture is vital for survival of eucalypts, especially as developing trees are increasingly subjected to spasmodic droughts and rising atmospheric CO2 levels. Trees were exposed to constant soil moisture deficits in 45 L pots (30–50% below field capacity), while atmospheric CO2 was raised to 700 μL CO2 L–1 in matched glasshouses using a hierarchical, multi-factorial design. Enrichment with CO2 stimulated shoot growth rates for 12–15 weeks in well-watered trees but after six months of CO2 enrichment, shoot biomasses were not significantly heavier (30% stimulation) in ambient conditions. By contrast, constant drought arrested shoot growth after 20 weeks under ambient conditions, whereas elevated CO2 sustained growth in drought and ultimately doubled the shoot biomass relative to ambient conditions. These growth responses were achieved through an enhancement of lateral branching up to 8-fold due to CO2 enrichment. In spite of larger transpiring canopies, CO2 enrichment also improved the daytime water status of leaves of droughted trees. Stem xylem development was highly regulated, with vessels per unit area and cross sectional area of xylem vessels in stems correlated inversely across all treatments. Furthermore, vessel numbers related to the numbers of leaves on lateral branches, broadly supporting predictions arising from Pipe Model Theory that the area of conducting tissue should correlate with leaf area. Diminished water use of trees in drought coincided with a population of narrower xylem vessels, constraining hydraulic capacity of stems. Commensurate with the positive effects of elevated CO2 on growth, development and leaf water relations of droughted trees, the capacity for long-distance water transport also increased.
Leaf canopy architecture determines light interception and carbon gain in wild and domesticated Oryza species
Publisher: Elsevier BV
Date: 11-2018
Rubisco activity is associated with photosynthetic thermotolerance in a wild rice (Oryza meridionalis)
Publisher: Wiley
Date: 19-03-2012
DOI: 10.1111/J.1399-3054.2012.01597.X
Abstract: Oryza meridionalis is a wild species of rice, endemic to tropical Australia. It shares a significant genome homology with the common domesticated rice Oryza sativa. Exploiting the fact that the two species are highly related but O. meridionalis has superior heat tolerance, experiments were undertaken to identify the impact of temperature on key events in photosynthesis. At an ambient CO(2) partial pressure of 38 Pa and irradiance of 1500 µmol quanta m(-2) s(-1), the temperature optimum of photosynthesis was 33.7 ± 0.8°C for O. meridionalis, significantly higher than the 30.6 ± 0.7°C temperature optimum of O. sativa. To understand the basis for this difference, we measured gas exchange and rubisco activation state between 20 and 42°C and modeled the response to determine the rate-limiting steps of photosynthesis. The temperature response of light respiration (R(light)) and the CO(2) compensation point in the absence of respiration (Γ(*)) were determined and found to be similar for the two species. C3 photosynthesis modeling showed that despite the difference in susceptibility to high temperature, both species had a similar temperature-dependent limitation to photosynthesis. Both rice species were limited by ribulose-1,5-bisphosphate (RuBP) regeneration at temperatures of 25 and 30°C but became RuBP carboxylation limited at 35 and 40°C. The activation state of rubisco in O. meridionalis was more stable at higher temperatures, explaining its greater heat tolerance compared with O. sativa.
Distribution of Protein Synthesized by Seedlings of Oryza sativa Grown in Anoxia
Publisher: Elsevier BV
Date: 06-1986
Turgor Pressure in Mechanically Impeded Lupin Roots
Publisher: CSIRO Publishing
Date: 1990
DOI: 10.1071/PP9900049
Abstract: Seedlings of lupin (Lupinus angustifolius cv. 75A-258) were grown in cores of sandy loam which was compacted to bulk densities of 1.6 and 1.8 Mg m-3 . There was a substantial decrease in root elongation rate at the higher bulk density. After 4-7 d, roots were rinsed free of soil and cl ed loosely in a Perspex block for measurement of turgor pressure (P) using a pressure probe. Measurements were made at 3-4 positions on each root, each estimation taking 2 min. Turgor pressures in the terminal 15 mm of the axes ranged between 0.213 and 0.530 at 1.6 Mg m-3 and 0.210 and 0.570 MPa at 1.8 Mg m-3 mean P values were 0.365 and 0.351 MPa in roots growing at 1.6 and 1.8 Mg m-3, respectively. These measurements were made on roots removed from the soil P could have been greater in roots still growing in compact soil. Anatomical studies showed that the distal boundary of the zone of cell expansion was 2-4 mm nearer the apex in roots growing at 1.8 than at 1.6 Mg m-3. Using this information, we showed that the mean P of expanding tissue was the same in roots of the two treatments. The apparent rise in P near the apex of roots at 1.8 Mg m-3 was not statistically significant. Primary roots growing against high mechanical impedance had a 34% lower rate of elongation and a 22% greater diameter, resulting in nearly identical rates of volume expansion (35.1 and 34.9 mm3 d-1 at 1.6 and 1.8 Mg m-3 respectively). Furthermore, the rate of O2 uptake was the same in 10 mm root apices from both treatments so that there was no evidence that the carbohydrate requirement for respiration was enhanced by high soil strength. Moreover, while mechanical impedance decreased root elongation, it did not significantly affect our estimate of P. We believe that P in lupin roots changes in response to mechanical impedance only when volume expansion or utilization of solutes are affected.
The first long-read nuclear genome assembly of Oryza australiensis, a wild rice from northern Australia
Publisher: Springer Science and Business Media LLC
Date: 25-06-2022
DOI: 10.1038/S41598-022-14893-5
Abstract: Oryza australiensis is a wild rice native to monsoonal northern Australia. The International Oryza Map Alignment Project emphasises its significance as the sole representative of the EE genome clade. Assembly of the O. australiensis genome has previously been challenging due to its high Long Terminal Repeat (LTR) retrotransposon (RT) content. Oxford Nanopore long reads were combined with Illumina short reads to generate a high-quality ~ 858 Mbp genome assembly within 850 contigs with 46× long read coverage. Reference-guided scaffolding increased genome contiguity, placing 88.2% of contigs into 12 pseudomolecules. After alignment to the Oryza sativa cv. Nipponbare genome, we observed several structural variations. PacBio Iso-Seq data were generated for five distinct tissues to improve the functional annotation of 34,587 protein-coding genes and 42,329 transcripts. We also report SNV numbers for three additional O. australiensis genotypes based on Illumina re-sequencing. Although genetic similarity reflected geographical separation, the density of SNVs also correlated with our previous report on variations in salinity tolerance. This genome re-confirms the genetic remoteness of the O. australiensis lineage within the O. officinalis genome complex. Assembly of a high-quality genome for O. australiensis provides an important resource for the discovery of critical genes involved in development and stress tolerance.
Understanding of the Interactive Effect of Waterlogging and Shade on Cotton (Gossypium hirsutum L.) Growth and Yield
Publisher: Elsevier BV
Date: 2015
The effect of oxygen deficiency on uptake and distribution of nutrients in maize plants
Publisher: Springer Science and Business Media LLC
Date: 02-1990
DOI: 10.1007/BF02851904
Analysis of growth components in roots of wheat seedlings exposed to low O2 concentrations
Publisher: Elsevier BV
Date: 07-1989
Sapwood development in Pinus radiata trees grown for three years at ambient and elevated carbon dioxide partial pressures
Publisher: Oxford University Press (OUP)
Date: 2003
Abstract: Clonal trees of Pinus radiata D. Don were grown in open-top chambers at a field site in New Zealand for 3 years at ambient (37 Pa) or elevated (65 Pa) carbon dioxide (CO2) partial pressure. Nitrogen (N) was supplied to half of the trees in each CO2 treatment, at 15 g N m-2 in the first year and 60 g N m-2 in the subsequent 2 years (high-N treatment). Trees in the low-N treatment were not supplied with N but received the same amount of other nutrients as trees in the high-N treatment. In the first year, stem basal area increased more in trees growing at elevated CO2 partial pressure and high-N supply than in control trees, suggesting a positive interaction between these resources. However, the relative rate of growth became the same across trees in all treatments after 450 days, resulting in trees growing at elevated CO2 partial pressure and high-N supply having larger basal areas than trees in the other treatments. Sapwood N content per unit dry mass was consistently about 0.09% in all treatments, indicating that N status was not suppressed by elevated CO2 partial pressure. Thus, during the first year of growth, an elevated CO2 partial pressure enhanced carbon (C) and N storage in woody stems, but there was no further stimulus to C and N deposition after the first year. The chemical composition of sapwood was unaffected by elevated CO2 partial pressure, indicating that no additional C was sequestered through lignification. However, independent of the treatments, early wood was 13% richer in lignin than late wood. Elevated CO2 partial pressure decreased the proportion of sapwood occupied by the lumina of tracheids by up to 12%, indicating increased sapwood density in response to CO2 enrichment. This effect was probably a result of thicker tracheid walls rather than narrower lumina.
MicroRNA Profiling of Root Meristematic Zone in Contrasting Genotypes Reveals Novel Insight into in Rice Response to Water Deficiency
Publisher: Springer Science and Business Media LLC
Date: 23-12-2022
Aminoethoxyvinylglycine (AVG) ameliorates waterlogging-induced damage in cotton by inhibiting ethylene synthesis and sustaining photosynthetic capacity
Publisher: Springer Science and Business Media LLC
Date: 15-02-2015
Temperature response of mesophyll conductance in cultivated and wild Oryza species with contrasting mesophyll cell wall thickness
Publisher: Wiley
Date: 22-08-2011
DOI: 10.1111/J.1365-3040.2011.02398.X
Abstract: A critical component of photosynthetic capacity is the conductance of CO(2) from intercellular airspaces to the sites of CO(2) fixation in the stroma of chloroplasts, termed mesophyll conductance (g(m)). Leaf anatomy has been identified as an important determinant of g(m). There are few studies of the temperature response of g(m) and none has examined the implications of leaf anatomy. Hence, we compared a cultivar of Oryza sativa with two wild Oryza relatives endemic to the hot northern savannah of Australia, namely Oryza meridionalis and Oryza australiensis. All three species had similar leaf anatomical properties, except that the wild relatives had significantly thicker mesophyll cell walls than O. sativa. Thicker mesophyll cell walls in the wild rice species are likely to have contributed to the reduction in g(m) , which was associated with a greater drawdown of CO(2) into chloroplasts (C(i) -C(c) ) compared with O. sativa. Mesophyll conductance increased at higher temperatures, whereas the rate of CO(2) assimilation was relatively stable between 20 and 40 °C. Consequently, C(i) -C(c) decreased for all three species as temperature increased.
The effect of soil compaction on wheat during early tillering
Publisher: Wiley
Date: 05-1990
Genome survey sequencing of wild cotton (Gossypium robinsonii) reveals insights into proteomic responses of pollen to extreme heat
Publisher: Cold Spring Harbor Laboratory
Date: 28-08-2021
DOI: 10.1101/2021.08.27.457898
Abstract: Heat stress specifically affects fertility by impairing pollen viability but cotton wild relatives successfully reproduce in hot savannas where they evolved. An Australian heat-tolerant cotton ( Gossypium robinsonii ) was exposed to heat events during pollen development, then mature pollen was subjected to deep proteomic analysis using 57,023 predicted genes from a genomic database we assembled for the same species. Three stages of pollen development, including tetrads, uninucleate and binucleate microspores were exposed to 36°C or 40°C for 5 d and the resulting mature pollen was collected at anthesis (p-TE, p-UN and p-BN, respectively). Using SWATH-MS proteomic analysis, 2,704 proteins were identified and quantified across all pollen s les analyzed. Proteins predominantly decreased in abundance at all stages in response to heat, particularly after exposure of tetrads to 40°C. Functional enrichment analyses demonstrated that extreme heat increased the abundance of proteins that contributed to increased mRNA splicing via spliceosome, initiation of cytoplasmic translation and protein refolding in p-TE40. However, other functional categories that contributed to intercellular transport were inhibited in p-TE40, linked potentially to Rab proteins. We ascribe the resilience of reproductive processes in G. robinsonii at temperatures up to 40°C, relative to commercial cotton, to a targeted reduction in protein transport.
The phosphoproteome of rice leaves responds to water and nitrogen supply
Publisher: Royal Society of Chemistry (RSC)
Date: 4
DOI: 10.1039/D1MO00137J
Abstract: Quantitative phosphoproteomic analysis of rice plants grown with different levels of water supply and nitrogen supplementation revealed changes in phosphorylation of proteins involved in membrane transport, RNA processing and carbohydrate metabolism.
Drought × CO2 interactions in trees: A test of the low-intercellular CO2 concentration (Ci ) mechanism
Publisher: Wiley
Date: 03-11-2016
DOI: 10.1111/NPH.13715
Abstract: Models of tree responses to climate typically project that elevated atmospheric CO 2 concentration ( e C a ) will reduce drought impacts on forests. We tested one of the mechanisms underlying this interaction, the ‘low C i effect’, in which stomatal closure in drought conditions reduces the intercellular CO 2 concentration ( C i ), resulting in a larger relative enhancement of photosynthesis with e C a , and, consequently, a larger relative biomass response. We grew two Eucalyptus species of contrasting drought tolerance at ambient and elevated C a for 6–9 months in large pots maintained at 50% (drought) and 100% field capacity. Droughted plants did not have significantly lower C i than well‐watered plants, which we attributed to long‐term changes in leaf area. Hence, there should not have been an interaction between e C a and water availability on biomass, and we did not detect one. The xeric species did have higher C i than the mesic species, indicating lower water‐use efficiency, but both species exhibited similar responses of photosynthesis and biomass to e C a , owing to compensatory differences in the photosynthetic response to C i . Our results demonstrate that long‐term acclimation to drought, and coordination among species traits may be important for predicting plant responses to e C a under low water availability.
Response of extrafloral nectar production to elevated atmospheric carbon dioxide
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/BT18012
Abstract: Extrafloral nectar attracts ants, whose presence provides protection for the plant against herbivores. Extrafloral nectar is thus a critical component of many plant–insect mutualisms worldwide, so environmental perturbations that alter extrafloral nectar production or composition could be disruptive. The carbon–nutrient balance hypothesis predicts that under elevated CO2 the total volume of extrafloral nectar will increase but the proportion of the foliar carbohydrate pool secreted as extrafloral nectar will decrease, without any change in the sugar composition of the extrafloral nectar. We investigated the impact of elevated atmospheric CO2 on extrafloral nectar in an Australian wild cotton species, Gossypium sturtianum J.H.Willis. Under elevated CO2 there was an increase in the proportion of leaves actively producing nectar and a decrease in the nectar volume per active leaf. Elevated CO2 did not affect the total volume or composition of extrafloral nectar, but there was a change in how the nectar was distributed within the leaf canopy, as well as evidence of increased turnover of leaves and earlier onset of flowering. By the end of the study, there was no difference in the total resources allocated to extrafloral nectar under elevated CO2, which contrasts with the predictions of the carbon-nutrient balance hypothesis. Developmental changes, however, could affect the timing of extrafloral nectar production which could, in turn, alter the foraging patterns of ants and their defence of plants.
Protecting cotton crops under elevated CO2 from waterlogging by managing ethylene
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/FP17184
Abstract: Soil waterlogging and subsequent ethylene release from cotton (Gossypium hirsutum L.) tissues has been linked with abscission of developing cotton fruits. This glasshouse study investigates the effect of a 9-day waterlogging event and CO2 enrichment (eCO2, 700 parts per million (ppm)) on a fully linted cultivar ‘Empire’ and a lintless cotton mutant (5B). We hypothesised that cotton performance in extreme environments such as waterlogging can be improved through mitigating ethylene action. Plants were grown at 28 : 20°C day : night temperature, 50–70% relative humidity and a 14 : 10 light : dark photoperiod under natural light and were exposed to waterlogging and eCO2 at early reproductive growth. Ethylene synthesis was inhibited by spraying aminoethoxyvinylglycine (830 ppm) 1 day before waterlogging. Waterlogging significantly increased ethylene release from both cotton genotypes, although fruit production was significantly inhibited only in Empire. Aminoethoxyvinylglycine consistently reduced waterlogging-induced abscission of fruits, mainly in Empire. Limited damage to fruits in 5B, despite increased ethylene production during waterlogging, suggested that fruit abscission in 5B was inhibited by disrupting ethylene metabolism genetically. Elevated CO2 promoted fruit production in both genotypes and was more effective in 5B than in Empire plants. Hence 5B produced more fruits than Empire, providing additional sinks (existing and new fruit) that enhanced the response to CO2 enrichment.
Genome survey sequencing of wild cotton (Gossypium robinsonii) reveals insights into proteomic responses of pollen to extreme heat
Publisher: Wiley
Date: 17-02-2022
DOI: 10.1111/PCE.14268
Abstract: Heat stress specifically affects fertility by impairing pollen viability but cotton wild relatives successfully reproduce in hot savannas where they evolved. An Australian arid‐zone cotton ( Gossypium robinsonii ) was exposed to heat events during pollen development then mature pollen was subjected to deep proteomic analysis using 57 023 predicted genes from a genomic database we assembled for the same species. Three stages of pollen development, including tetrads (TEs), uninucleate microspores (UNs) and binucleate microspores (BNs) were exposed to 36°C or 40°C for 5 days and the resulting mature pollen was collected at anthesis (p‐TE, p‐UN and p‐BN, respectively). Using the sequential windowed acquisition of all theoretical mass spectra proteomic analysis, 2704 proteins were identified and quantified across all pollen s les analysed. Proteins predominantly decreased in abundance at all stages in response to heat, particularly after exposure of TEs to 40°C. Functional enrichment analyses demonstrated that extreme heat increased the abundance of proteins that contributed to increased messenger RNA splicing via spliceosome, initiation of cytoplasmic translation and protein refolding in p‐TE40. However, other functional categories that contributed to intercellular transport were inhibited in p‐TE40, linked potentially to Rab proteins. We ascribe the resilience of reproductive processes in G. robinsonii at temperatures up to 40°C, relative to commercial cotton, to a targeted reduction in protein transport.
Shotgun Proteomic Analysis of Long-distance Drought Signaling in Rice Roots
Publisher: American Chemical Society (ACS)
Date: 02-12-2011
DOI: 10.1021/PR2008779
Abstract: Rice (Oryza sativa L. cv. IR64) was grown in split-root systems to analyze long-distance drought signaling within root systems. This in turn underpins how root systems in heterogeneous soils adapt to drought. The approach was to compare four root tissues: (1) fully watered (2) fully droughted and split-root systems where (3) one-half was watered and (4) the other half was droughted. This was specifically aimed at identifying how droughted root tissues altered the proteome of adjacent wet roots by hormone signals and how wet roots reciprocally affected dry roots hydraulically. Quantitative label-free shotgun proteomic analysis of four different root tissues resulted in identification of 1487 nonredundant proteins, with nearly 900 proteins present in triplicate in each treatment. Drought caused surprising changes in expression, most notably in partially droughted roots where 38% of proteins were altered in level compared to adjacent watered roots. Specific functional groups changed consistently in drought. Pathogenesis-related proteins were generally up-regulated in response to drought and heat-shock proteins were totally absent in roots of fully watered plants. Proteins involved in transport and oxidation-reduction reactions were also highly dependent upon drought signals, with the former largely absent in roots receiving a drought signal while oxidation-reduction proteins were strongly present during drought. Finally, two functionally contrasting protein families were compared to validate our approach, showing that nine tubulins were strongly reduced in droughted roots while six chitinases were up-regulated, even when the signal arrived remotely from adjacent droughted roots.
Growth Dynamics of Mechanically Impeded Lupin Roots: does Altered Morphology Induce Hypoxia?
Publisher: Oxford University Press (OUP)
Date: 18-08-2005
DOI: 10.1093/AOB/MCI243
The uptake of phosphate by Carex species from oligotrophic to eutrophic swamp habitats
Publisher: Wiley
Date: 08-1980
Factors which affect the growth of grain legumes on a solonized brown soil. II. Genotypic responses to soil chemical factors
Publisher: CSIRO Publishing
Date: 1991
DOI: 10.1071/AR9910107
Abstract: Lupins (Lupinus angustifolius cvv. Yandee, 75A-258 and P22872, and L. pilosus cv. P20957) and field peas ( cv. Dundale) were grown in the glasshouse in a sieved solonized brown soil. The soil was taken from sequentially deeper zones in the B horizon of the natural profile (8-83 cm below the surface). The pH (in CaCl2) increased from c. 6.3 to c. 8.2 with depth while sodium and chloride concentrations reached 83 and 62 mol m-3 (soil solution) respectively in the deepest unfertilized subsoil. Sodium concentrations reached 159 mol m-3 when the subsoil was fertilized. When plants were grown in the deepest subsoil, the growth of shoots and roots was inhibited by up to 75% in L. angustifolius but less severely in L. pilosus and pea. Roots of pea were affected least by the deep subsoil. Shoots of L. angustifolius, but not L. pilosus or pea, had severe chlorosis in the expanding tissue and necrosis of the oldest leaflets when grown on the deepest soil. Expanded leaflets of L. angustifolius had sodium and chloride concentrations up to 200 mol m-3 while iron concentrations were less than 208g g-1 dry weight in expanding tissues. Concentrations of manganese and zinc exceeded requirements for maximum growth but copper concentrations were sufficiently low to suggest deficiency in growing tissue of Yandee and 75A-258. No symptoms of deficiency were apparent. It is concluded that adverse chemical factors in the subsoil restrict root growth of L. angustifolius in the field. L. pilosus and field peas, on the other hand, appear to be significantly better adapted to these sodic, alkaline subsoils.
Photosynthetic traits of Australian wild rice (Oryza australiensis) confer tolerance to extreme daytime temperatures
Publisher: Springer Science and Business Media LLC
Date: 08-01-2022
DOI: 10.1007/S11103-021-01210-3
Abstract: A wild relative of rice from the Australian savannah was compared with cultivated rice, revealing thermotolerance in growth and photosynthetic processes and a more robust carbon economy in extreme heat. Above ~ 32 °C, impaired photosynthesis compromises the productivity of rice. We compared leaf tissues from heat-tolerant wild rice ( Oryza australiensis ) with temperate-adapted O . sativa after sustained exposure to heat, as well as diurnal heat shock. Leaf elongation and shoot biomass in O . australiensis were unimpaired at 45 °C, and soluble sugar concentrations trebled during 10 h of a 45 °C shock treatment. By contrast, 45 °C slowed growth strongly in O. sativa . Chloroplastic CO 2 concentrations eliminated CO 2 supply to chloroplasts as the basis of differential heat tolerance. This directed our attention to carboxylation and the abundance of the heat-sensitive chaperone Rubisco activase (Rca) in each species. Surprisingly, O . australiensis leaves at 45 °C had 50% less Rca per unit Rubisco, even though CO 2 assimilation was faster than at 30 °C. By contrast, Rca per unit Rubisco doubled in O. sativa at 45 °C while CO 2 assimilation was slower, reflecting its inferior Rca thermostability. Plants grown at 45 °C were simultaneously exposed to 700 ppm CO 2 to enhance the CO 2 supply to Rubisco. Growth at 45 °C responded to CO 2 enrichment in O. australiensis but not O. sativa , reflecting more robust carboxylation capacity and thermal tolerance in the wild rice relative.
Quantitative proteomic analysis of two different rice varieties reveals that drought tolerance is correlated with reduced abundance of photosynthetic machinery and increased abundance of ClpD1 proteas
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.JPROT.2016.05.014
Abstract: Rice is the major staple food for more than half of world's population. As global climate changes, we are observing more floods, droughts and severe heat waves. Two rice cultivars with contrasting genetic backgrounds and levels of tolerance to drought, Nipponbare and IAC1131, were used in this study. Four-week-old seedlings of both cultivars were grown in large soil volumes and then exposed to moderate and extreme drought for 7days, followed by 3days of re-watering. Mature leaves were harvested from plants from each treatment for protein extraction and subsequent shotgun proteomic analysis, with validation of selected proteins by western blotting. Gene Ontology (GO) annotations of differentially expressed proteins provide insights into the metabolic pathways that are involved in drought stress resistance. Our data indicate that IAC1131 appears to be better able to cope with stressful conditions by upregulating a suite of stress and defence response related proteins. Nipponbare, in contrast, lacks the range of stress responses shown by the more stress tolerant variety, and responds to drought stress by initiating a partial shutdown of chlorophyll biosynthesis in an apparent attempt to preserve resources. In this study, two rice genotypes with contrasting drought tolerance were exposed to soil water deficits, and proteomic changes were observed in mature leaf laminae. Plants were well watered and then switched to conditions of either moderate drought or extreme drought followed by three days of recovery. Proteins were identified and quantified using both label-free and Tandem Mass Tag multiplexing approaches. Several biochemical pathways were significantly altered in response to water deficit. Most notably, the up-regulation of ClpD1 protease responded strongly in the drought-tolerant landrace this protein is typically involved in heat and osmotic stress response. In contrast, porphyrin and chlorophyll biosynthesis pathways were down-regulated, indicating suppression of the photosynthetic machinery.
Differential metabolic response of cultured rice (Oryza sativa) cells exposed to high‐ and low‐temperature stress
Publisher: Wiley
Date: 08-2010
Abstract: Global mean temperatures are expected to rise by 2-4.5 degrees C by 2100, accompanied by an increase in frequency and litude of extreme temperature events. Greater climatic extremes and an expanded range of cultivation will expose rice to increasing stress in the future. Understanding gene expression in disparate thermal regimes is important for the engineering of cultivars with tolerance to nonoptimal temperatures. Our study investigated the proteomic responses of rice cell suspension cultures to sudden temperature changes. Cell cultures grown at 28 degrees C were subjected to 3-day exposure to 12 or 20 degrees C for low-temperature stress, and 36 or 44 degrees C for high-temperature stress. Quantitative label-free shotgun proteomic analysis was performed on biological triplicates of each treatment. Over 1900 proteins were expressed in one or more temperature treatments, and, of these, more than 850 were found to be responsive to either of the temperature extremes. These temperature-responsive proteins included more than 300 proteins which were uniquely expressed at either 12 or 44 degrees C. Our study also identified 40 novel stress-response proteins and observed that switching between the classical and the alternative pathways of sucrose metabolism occurs in response to extremes of temperature.
Volatile isoprenoid emissions from plastid to planet
Publisher: Wiley
Date: 12-11-2012
DOI: 10.1111/NPH.12021
Abstract: Approximately 1–2% of net primary production by land plants is re‐emitted to the atmosphere as isoprene and monoterpenes. These emissions play major roles in atmospheric chemistry and air pollution–climate interactions. Phenomenological models have been developed to predict their emission rates, but limited understanding of the function and regulation of these emissions has led to large uncertainties in model projections of air quality and greenhouse gas concentrations. We synthesize recent advances in erse fields, from cell physiology to atmospheric remote sensing, and use this information to propose a simple conceptual model of volatile isoprenoid emission based on regulation of metabolism in the chloroplast. This may provide a robust foundation for scaling up emissions from the cellular to the global scale.
Repair Effectiveness of Damaged RC Beams with Web Opening Using CFRP and Steel Plates
Publisher: Jordan Journal of Civil Engineering
Date: 04-2016
Well-Designed Experiments Make Proteomic Studies on Stressed Plants Meaningful
Publisher: Springer International Publishing
Date: 2016
Physiological and molecular changes in Oryza meridionalis Ng., a heat-tolerant species of wild rice
Publisher: Oxford University Press (OUP)
Date: 09-10-2009
DOI: 10.1093/JXB/ERP294
A survey of leaf phosphorus fractions and leaf economic traits among 12 co-occurring woody species on phosphorus-impoverished soils
Publisher: Springer Science and Business Media LLC
Date: 04-04-2023
DOI: 10.1007/S11104-023-06001-X
Abstract: The leaf economic spectrum (LES) is related to dry mass and nutrient investments towards photosynthetic processes and leaf structures, and to the duration of returns on those investments (leaf lifespan, LL). Phosphorus (P) is a key limiting nutrient for plant growth, yet it is unclear how the allocation of leaf P among different functions is coordinated with the LES. We addressed this question among 12 evergreen woody species co-occurring on P-impoverished soils in south-eastern Australia. Leaf ‘economic’ traits, including LL, leaf mass per area (LMA), light-saturated net photosynthetic rate per mass (A mass ), dark respiration rate, P concentration ([P total ]), nitrogen concentration, and P resorption, were measured for three pioneer and nine non-pioneer species. Leaf P was separated into five functional fractions: orthophosphate P (P i ), metabolite P (P M ), nucleic acid P (P N ), lipid P (P L ), and residual P (P R phosphorylated proteins and unidentified compounds that contain P). LL was negatively correlated with A mass and positively correlated with LMA, representing the LES. Pioneers occurred towards the short-LL end of the spectrum and exhibited higher [P total ] than non-pioneer species, primarily associated with higher concentrations of P i , P N and P L . There were no significant correlations between leaf P fractions and LL or LMA, while A mass was positively correlated with the concentration of P R . Allocation of leaf P to different fractions varied substantially among species. This variation was partially associated with the LES, which may provide a mechanism underlying co-occurrence of species with different ecological strategies under P limitation.
A study of the impaired growth of roots of Zea mays seedlings at low oxygen concentrations
Publisher: Wiley
Date: 04-1985
Light interception efficiency explained by two simple variables: A test using a diversity of small- to medium-sized woody plants
Publisher: Wiley
Date: 08-11-2012
DOI: 10.1111/J.1469-8137.2011.03943.X
Abstract: • Plant light interception efficiency is a crucial determinant of carbon uptake by in idual plants and by vegetation. Our aim was to identify whole-plant variables that summarize complex crown architecture, which can be used to predict light interception efficiency. • We gathered the largest database of digitized plants to date (1831 plants of 124 species), and estimated a measure of light interception efficiency with a detailed three-dimensional model. Light interception efficiency was defined as the ratio of the hemispherically averaged displayed to total leaf area. A simple model was developed that uses only two variables, crown density (the ratio of leaf area to total crown surface area) and leaf dispersion (a measure of the degree of aggregation of leaves). • The model explained 85% of variation in the observed light interception efficiency across the digitized plants. Both whole-plant variables varied across species, with differences in leaf dispersion related to leaf size. Within species, light interception efficiency decreased with total leaf number. This was a result of changes in leaf dispersion, while crown density remained constant. • These results provide the basis for a more general understanding of the role of plant architecture in determining the efficiency of light harvesting.
Unique and Shared Proteome Responses of Rice Plants (Oryza sativa) to Individual Abiotic Stresses
Publisher: MDPI AG
Date: 08-12-2022
Abstract: Food safety of staple crops such as rice is of global concern and is at the top of the policy agenda worldwide. Abiotic stresses are one of the main limitations to optimizing yields for sustainability, food security and food safety. We analyzed proteome changes in Oryza sativa cv. Nipponbare in response to five adverse abiotic treatments, including three levels of drought (mild, moderate, and severe), soil salinization, and non-optimal temperatures. All treatments had modest, negative effects on plant growth, enabling us to identify proteins that were common to all stresses, or unique to one. More than 75% of the total of differentially abundant proteins in response to abiotic stresses were specific to in idual stresses, while fewer than 5% of stress-induced proteins were shared across all abiotic constraints. Stress-specific and non-specific stress-responsive proteins identified were categorized in terms of core biological processes, molecular functions, and cellular localization.
Drought by CO2 interactions in trees: a test of the water savings mechanism
Publisher: Wiley
Date: 16-02-2021
DOI: 10.1111/NPH.17233
Abstract: Elevated atmospheric CO 2 (eC a ) may benefit plants during drought by reducing stomatal conductance ( g s ) but any ‘water savings effect’ could be neutralized by concurrent stimulation of leaf area. We investigated whether eC a enhanced water savings, thereby ameliorating the impact of drought on carbon and water relations in trees. We report leaf‐level gas exchange and whole‐plant and soil water relations during a short‐term dry‐down in two Eucalyptus species with contrasting drought tolerance. Plants had previously been established for 9 to 11 months in steady‐state conditions of ambient atmospheric CO 2 (aC a ) and eC a , with half of each treatment group exposed to sustained drought for 5 to 7 months. The lower stomatal conductance under eC a did not lead to soil moisture savings during the dry‐down due to the counteractive effect of increased whole‐plant leaf area. Nonetheless, eC a ‐grown plants maintained higher photosynthetic rates and leaf water potentials, making them less stressed during the dry‐down, despite being larger. These effects were more pronounced in the xeric species than the mesic species, and in previously water‐stressed plants. Our findings indicate that eC a may enhance plant performance during drought despite a lack of soil water savings, especially in species with more conservative growth and water‐use strategies.
How Proteomics Contributes to Our Understanding of Drought Tolerance
Publisher: Springer International Publishing
Date: 2016
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