Kathleen Soole

The General Transcription Repressor TaDr1 Is Co-expressed With TaVrn1 and TaFT1 in Bread Wheat Under Drought

Publisher: Frontiers Media SA

Date: 08-02-2019

DOI: 10.3389/FGENE.2019.00063

Regulation of Alternative Pathway Activity in Plant Mitochondria

Publisher: Oxford University Press (OUP)

Date: 03-1991

DOI: 10.1104/PP.95.3.948

AtNDB2 is the main external NADH dehydrogenase in mitochondria and is important for tolerance to environmental stress

Publisher: Oxford University Press (OUP)

Date: 13-08-2019

DOI: 10.1104/PP.19.00877

Intracellular vesicle trafficking genes, RabC-GTP, are highly expressed under salinity and rapid dehydration but down-regulated by drought in leaves of chickpea (Cicer arietinum L.)

Publisher: Frontiers Media SA

Date: 07-02-2019

DOI: 10.3389/FGENE.2019.00040

The role of light in the regulation of ascorbate metabolism during berry development in the cultivated grapevineVitis viniferaL.

Publisher: Wiley

Date: 29-03-2011

DOI: 10.1002/JSFA.4376

Abstract: The accumulation of L-ascorbate (Asc) in fruits is influenced by environmental factors including light quantity. Fruit exposure to ambient light is often reduced by the surrounding leaf canopy, and can be altered by cultivation practices. The influence of reduced sunlight exposure on the accumulation of Asc and its catabolites was investigated in field-grown berries of the cultivated grapevine Vitis vinifera L. cv. Shiraz. Growth under sunlight-eliminated conditions resulted in reduced berry fresh weight, chlorosis and a reduced total L-ascorbate pool size. The concentration of the Asc catabolite L-tartaric acid (TA) was reduced in berries grown without light. Conversely, concentrations of oxalic acid (OA), an alternative catabolite of Asc, and malic acid (MA), were unaffected by shading the berries during development. Brief and significant reductions in transcription of the Asc metabolic genes were observed in shade-grown berries after 4 weeks of dark acclimatisation whilst a key TA biosynthetic gene was not regulated by light. The results demonstrate that light-regulation of Asc and TA occurs only at brief stages of development and that OA and MA accumulation is light independent. Additionally, the comparable ratios of TA product to Asc precursor under both light regimes suggest that the ersion of Asc to TA is driven by factors that are not responsive to light. These findings suggest that an altered light regime is not the key to manipulating TA or MA levels in the harvested berry.

Genes Encoding Transcription Factors TaDREB5 and TaNFYC-A7 Are Differentially Expressed in Leaves of Bread Wheat in Response to Drought, Dehydration and ABA

Publisher: Frontiers Media SA

Date: 27-09-2018

DOI: 10.3389/FPLS.2018.01441

Regulation of malate metabolism in grape berry and other developing fruits

Publisher: Elsevier BV

Date: 07-2009

DOI: 10.1016/J.PHYTOCHEM.2009.08.006

Abstract: Organic acids are present in all plants, supporting numerous and varied facets of cellular metabolism. The type of organic acid found, and the levels to which they accumulate are extremely variable between species, developmental stages and tissue types. Acidity plays important roles in the organoleptic properties of plant tissues, where ex les of both enhanced and reduced palatability can be ascribed to the presence of specific organic acids. In fruits, sourness is generally attributed to proton release from acids such as citric, malic, oxalic, quinic, succinic and tartaric, while the anion forms each contribute a distinct taste. Acidity imposes a strong influence on crop quality, and is an important factor in deciding the harvest date, particularly for fruits where acidity is important for further processing, as in wine grapes. In the grape, as for many other fruits, malate is one of the most prevalent acids, and is an important participant in numerous cellular functions. The accumulation of malate is thought to be due in large part to de novo synthesis in fruits such as the grape, through metabolism of assimilates translocated from leaf tissues, as well as photosynthetic activity within the fruit itself. During ripening, the processes through which malate is catabolised are of interest for advancing metabolic understanding, as well as for potential crop enhancement through agricultural or molecular practices. A body of literature describes research that has begun to unravel the regulatory mechanisms of enzymes involved in malate metabolism during fruit development, through exploration of protein and gene transcript levels. Datasets derived from a series of recent microarray experiments comparing transcript levels at several stages of grape berry development have been revisited, and are presented here with a focus on transcripts associated with malate metabolism. Developmental transcript patterns for enzymes potentially involved in grape malate metabolism have shown that some flux may occur through pathways that are less commonly regarded in ripening fruit, such as aerobic ethanol production. The data also suggest pyruvate as an important intermediate during malate catabolism in fruit. This review will combine an analysis of microarray data with information available on protein and enzyme activity patterns in grapes and other fruits, to explore pathways through which malate is conditionally metabolised, and how these may be controlled in response to developmental and climatic changes. Currently, an insufficient understanding of the complex pathways through which malate is degraded, and how these are regulated, prevents targeted genetic manipulation aimed at modifying fruit malate metabolism in response to environmental conditions.

Two O-methyltransferases involved in the biosynthesis of methoxypyrazines: grape-derived aroma compounds important to wine flavour

Publisher: Springer Science and Business Media LLC

Date: 23-06-2010

DOI: 10.1007/S11103-010-9655-Y

Abstract: Methoxypyrazines (MPs) are volatile, grape-derived aroma compounds that contribute to the distinct herbaceous characters of some wines. Although the full pathway leading to MP production has not been elucidated, there is strong evidence that the final step involves the methylation of non-volatile hydroxypyrazine (HP) precursors. Two cDNA encoding O-methyltransferases (OMTs) that have homology to an enzyme previously purified and shown to catalyse the methylation of HPs were isolated from Cabernet Sauvignon. Recombinant protein from the cDNAs (VvOMT1 and VvOMT2) was produced in E. coli and activity assays demonstrated that both encode OMTs able to methylate HPs to produce MPs, however both showed greatest activity against the flavonol quercetin. VvOMT1 has higher catalytic activity against isobutyl hydroxypyrazine compared to isopropyl hydroxypyrazine, whereas the converse is true for VvOMT2. The timing of the expression of VvOMT1 in the skin and the flesh of developing Cabernet Sauvignon grape berries was associated with the period of MP accumulation in these tissues, while VvOMT2 expression was greatest in roots, which were found to contain high levels of MPs. The MP composition of these tissues also reflects the relative levels of expression of these genes and their substrate preference. The identification of genes responsible for MP production in grapevine will help in understanding the effect of different viticultural and environmental factors on MP accumulation.

A methyltransferase essential for the methoxypyrazine‐derived flavour of wine

Publisher: Wiley

Date: 21-05-2013

DOI: 10.1111/TPJ.12224

Abstract: Methoxypyrazines are a family of potent volatile compounds of erse biological significance. They are used by insects and plants in chemical defence, are present in many vegetables and fruit and, in particular, impart herbaceous/green/vegetal sensory attributes to wines of certain varieties, including Cabernet Sauvignon. While pathways for methoxypyrazine biosynthesis have been postulated, none of the steps have been confirmed genetically. We have used the F2 progeny of a cross between a rapid flowering grapevine dwarf mutant, which does not produce 3-isobutyl-2-methoxypyrazine (IBMP), and Cabernet Sauvignon to identify the major locus responsible for accumulation of IBMP in unripe grape berries. Two candidate methyltransferase genes within the locus were identified and one was significantly associated with berry IBMP levels using association mapping. The enzyme encoded by this gene (VvOMT3) has high affinity for hydroxypyrazine precursors of methoxypyrazines. The gene is not expressed in the fruit of Pinot varieties, which lack IBMP, but is expressed in Cabernet Sauvignon at the time of accumulation of IBMP in the fruit. The results suggest that VvOMT3 is responsible for the final step in methoxypyrazine synthesis in grape berries and is the major determinant of IBMP production.

Hydrocarbon Phytoremediation in the FamilyFabacea—A Review

Publisher: Informa UK Limited

Date: 18-02-2011

DOI: 10.1080/15226514.2010.495143

Abstract: Currently, studies often focus on the use of Poaceae species (grasses) for phytoremediation of hydrocarbon-contaminated soils. Research into the use of Fabaceae species (legumes) to remediate hydrocarbons in soils has been conducted, but these plants are commonly overlooked due to slower recorded rates of degradation compared with many grass species. Evidence in the literature suggests that in some cases Fabaceae species may increase total degradation of hydrocarbons and stimulate degradative capacity of the soil microbial community, particularly for contaminants which are normally more recalcitrant to degradation. As many recalcitrant hydrocarbons have negative impacts on human and ecosystem health, development of remediation options is crucial. Reconsideration of Fabaceae species for removal of such contaminants may lead to environmentally and economically sustainable technologies for remediation of contaminated sites.

Genomic structure and expression of alternative oxidase genes in legumes

Publisher: Wiley

Date: 06-2019

DOI: 10.1111/PCE.13161

Abstract: Mitochondria isolated from chickpea (Cicer arietinum) possess substantial alternative oxidase (AOX) activity, even in non-stressed plants, and one or two AOX protein bands were detected immunologically, depending on the organ. Four different AOX isoforms were identified in the chickpea genome: CaAOX1 and CaAOX2A, B and D. CaAOX2A was the most highly expressed form and was strongly expressed in photosynthetic tissues, whereas CaAOX2D was found in all organs examined. These results are very similar to those of previous studies with soybean and siratro. Searches of available databases showed that this pattern of AOX genes and their expression was common to at least 16 different legume species. The evolution of the legume AOX gene family is discussed, as is the in vivo impact of an inherently high AOX capacity in legumes on growth and responses to environmental stresses.

Identification of alternative mitochondrial electron transport pathway components in chickpea indicates a differential response to salinity stress between cultivars

Publisher: MDPI AG

Date: 28-05-2020

DOI: 10.3390/IJMS21113844

Abstract: All plants contain an alternative electron transport pathway (AP) in their mitochondria, consisting of the alternative oxidase (AOX) and type 2 NAD(P)H dehydrogenase (ND) families, that are thought to play a role in controlling oxidative stress responses at the cellular level. These alternative electron transport components have been extensively studied in plants like Arabidopsis and stress inducible isoforms identified, but we know very little about them in the important crop plant chickpea. Here we identify AP components in chickpea (Cicer arietinum) and explore their response to stress at the transcript level. Based on sequence similarity with the functionally characterized proteins of Arabidopsis thaliana, five putative internal (matrix)-facing NAD(P)H dehydrogenases (CaNDA1-4 and CaNDC1) and four putative external (inter-membrane space)-facing NAD(P)H dehydrogenases (CaNDB1-4) were identified in chickpea. The corresponding activities were demonstrated for the first time in purified mitochondria of chickpea leaves and roots. Oxidation of matrix NADH generated from malate or glycine in the presence of the Complex I inhibitor rotenone was high compared to other plant species, as was oxidation of exogenous NAD(P)H. In leaf mitochondria, external NADH oxidation was stimulated by exogenous calcium and external NADPH oxidation was essentially calcium dependent. However, in roots these activities were low and largely calcium independent. A salinity experiment with six chickpea cultivars was used to identify salt-responsive alternative oxidase and NAD(P)H dehydrogenase gene transcripts in leaves from a three-point time series. An analysis of the Na:K ratio and Na content separated these cultivars into high and low Na accumulators. In the high Na accumulators, there was a significant up-regulation of CaAOX1, CaNDB2, CaNDB4, CaNDA3 and CaNDC1 in leaf tissue under long term stress, suggesting the formation of a stress-modified form of the mitochondrial electron transport chain (mETC) in leaves of these cultivars. In particular, stress-induced expression of the CaNDB2 gene showed a striking positive correlation with that of CaAOX1 across all genotypes and time points. The coordinated salinity-induced up-regulation of CaAOX1 and CaNDB2 suggests that the mitochondrial alternative pathway of respiration is an important facet of the stress response in chickpea, in high Na accumulators in particular, despite high capacities for both of these activities in leaf mitochondria of non-stressed chickpeas.

Advantages of Amplifluor-like SNP markers over KASP in plant genotyping

Publisher: Springer Science and Business Media LLC

Date: 12-2017

DOI: 10.1186/S12870-017-1197-X

Glycosyl‐phosphatidylinositol‐anchor addition signals are processed in Nicotiana tabacum

Publisher: Wiley

Date: 2000

DOI: 10.1046/J.1365-313X.2000.00651.X

Abstract: Recent studies have demonstrated the existence of glycosyl-phosphatidylinositol (GPI)-anchored proteins in higher plants. In this study we tested whether GPI-addition signals from erse evolutionary sources would function to link a GPI-anchor to a reporter protein in plant cells. Tobacco protoplasts were transiently transfected with a truncated form of the Clostridium thermocellum endoglucanase E reporter gene (celE') fused with a tobacco secretion signal (PR-1a) at the N-terminus and either a yeast (GAS1), mammalian (Thy-1) or putative plant (LeAGP-1) GPI-anchor addition signal at the C-terminus. The yeast and plant C-terminal signals were found to be capable of directing the addition of a GPI-anchor to the endoglucanase protein (EGE') as shown by the sensitivity of the lipid component of GPI to phosphatidylinositol-specific phospholipase C (PI-PLC) digestion. In contrast, the mammalian signal was poorly processed for anchor addition. When EGE' was fused to a truncated form of the LeAGP-1 signal (missing three amino acids predicted to be critical to signal cleavage and anchor addition), a GPI-anchor was not linked to the EGE' protein indicating the necessity for the missing amino acids. Our results show the conservation of the properties of GPI-signals in plant cells and that there may be some similar preferences in GPI-addition signal sequences for yeast and plant cells.

Expression level of the DREB2-type gene,identified with amplifluor SNP markers,correlates with performance,and tolerance to dehydration in bread wheat cultivars from northern Kazakhstan

Publisher: Frontiers Media SA

Date: 18-11-2016

DOI: 10.3389/FPLS.2016.01736

Development and validation of a radioimmunoassay for fish insulin-like growth factor I (IGF-I) and the effect of aquaculture related stressors on circulating IGF-I levels

Publisher: Elsevier BV

Date: 02-2004

DOI: 10.1016/J.YGCEN.2003.10.002

Abstract: This paper describes the development and validation of a commercially available radioimmunoassay (RIA) for the detection of fish insulin-like growth factor-I (IGF-I). The assay was developed using recombinant barramundi IGF-I as antigen and recombinant tuna IGF-I as radiolabelled tracer and standard. Assay sensitivity was 0.15 ng/ml, inter-assay variation was 16% (n = 9) and intra-assay variation was 3% (n = 10). Cross reactivity of less than 0.01% was found with salmon insulin, salmon IGF-II and barramundi IGF-II, less than 0.5% with human IGF-I and less than 1% with human IGF-II. Parallel dose-response inhibition curves were shown for barramundi (Lates calcarifer), coho salmon (Oncorhynchus kisutch), Southern Bluefin tuna (Thunnus maccoyii), tilapia (Oreochromis mossambicus), and seabream (Pagrus auratus) IGF-I. The assay was then used to measure stress related changes in different aquacultured fish species. Salt water acclimated Atlantic salmon smolts (Salmo salar) bathed for 2 h in fresh water showed significantly lower IGF-I concentrations than control smolts two days after the bath (53.1 compared to 32.1 ng/ml), with levels of IGF-I also lower in smolts exhibiting stunted growth (stunts). Capture and confinement of wild tuna in sea-cages resulted in a significant decrease in IGF-I levels (28 ng/ml) when compared to tuna captured and s led immediately (48 ng/ml), but had recovered to starting levels after 3 weeks (43 ng/ml). Handling and isolation in silver perch (Bidyanus bidyanus) led to a gradual decline in IGF-I over a 12 h period (36-19 ng/ml) but showed signs of recovery by 24 h (24 ng/ml) and had recovered fully 72 h after treatment (40 ng/ml). A similar trial in black bream (Acanthopagrus butcherii) showed comparable results with IGF-I levels gradually decreasing (40-26 ng/ml) over 24 h, results that were mirrored by cortisol concentrations which increased during this time (1-26 ng/ml). In the studies presented here changes in IGF-I levels were not observed for at least 3 h after exposure to the stressor. We suggest this is due to the endocrine nature of IGF-I regulation and the clearance rate of IGF-I in vivo.

TaDrAp1 and TaDrAp2, Partner Genes of a Transcription Repressor, Coordinate Plant Development and Drought Tolerance in Spelt and Bread Wheat

Publisher: MDPI AG

Date: 05-11-2020

DOI: 10.3390/IJMS21218296

Abstract: Down-regulator associated protein, DrAp1, acts as a negative cofactor (NC2α) in a transcription repressor complex together with another subunit, down-regulator Dr1 (NC2β). In binding to promotors and regulating the initiation of transcription of various genes, DrAp1 plays a key role in plant transition to flowering and ultimately in seed production. TaDrAp1 and TaDrAp2 genes were identified, and their expression and genetic polymorphism were studied using bioinformatics, qPCR analyses, a 40K Single nucleotide polymorphism (SNP) microarray, and Amplifluor-like SNP genotyping in cultivars of bread wheat (Triticum aestivum L.) and breeding lines developed from a cross between spelt (T. spelta L.) and bread wheat. TaDrAp1 was highly expressed under non-stressed conditions, and at flowering, TaDrAp1 expression was negatively correlated with yield capacity. TaDrAp2 showed a consistently low level of mRNA production. Drought caused changes in the expression of both TaDrAp1 and TaDrAp2 genes in opposite directions, effectively increasing expression in lower yielding cultivars. The microarray 40K SNP assay and Amplifluor-like SNP marker, revealed clear scores and allele discriminations for TaDrAp1 and TaDrAp2 and TaRht-B1 genes. Alleles of two particular homeologs, TaDrAp1-B4 and TaDrAp2-B1, co-segregated with grain yield in nine selected breeding lines. This indicated an important regulatory role for both TaDrAp1 and TaDrAp2 genes in plant growth, ontogenesis, and drought tolerance in bread and spelt wheat.

Energy costs of salt tolerance in crop plants

Publisher: Wiley

Date: 11-07-2019

DOI: 10.1111/NPH.15864

Abstract: Agriculture is expanding into regions that are affected by salinity. This review considers the energetic costs of salinity tolerance in crop plants and provides a framework for a quantitative assessment of costs. Different sources of energy, and modifications of root system architecture that would maximize water vs ion uptake are addressed. Energy requirements for transport of salt (NaCl) to leaf vacuoles for osmotic adjustment could be small if there are no substantial leaks back across plasma membrane and tonoplast in root and leaf. The coupling ratio of the H

Ascorbate metabolism and the developmental demand for tartaric and oxalic acids in ripening grape berries

Publisher: Springer Science and Business Media LLC

Date: 12-2009

DOI: 10.1186/1471-2229-9-145

Abstract: Fresh fruits are well accepted as a good source of the dietary antioxidant ascorbic acid (Asc, Vitamin C). However, fruits such as grapes do not accumulate exceptionally high quantities of Asc. Grapes, unlike most other cultivated fruits do however use Asc as a precursor for the synthesis of both oxalic (OA) and tartaric acids (TA). TA is a commercially important product in the wine industry and due to its acidifying effect on crushed juice it can influence the organoleptic properties of the wine. Despite the interest in Asc accumulation in fruits, little is known about the mechanisms whereby Asc concentration is regulated. The purpose of this study was to gain insights into Asc metabolism in wine grapes ( Vitis vinifera c.v. Shiraz.) and thus ascertain whether the developmental demand for TA and OA synthesis influences Asc accumulation in the berry. We provide evidence for developmentally differentiated up-regulation of Asc biosynthetic pathways and subsequent fluctuations in Asc, TA and OA accumulation. Rapid accumulation of Asc and a low Asc to dehydroascorbate (DHA) ratio in young berries was co-ordinated with up-regulation of three of the primary Asc biosynthetic (Smirnoff-Wheeler) pathway genes. Immature berries synthesised Asc in-situ from the primary pathway precursors D -mannose and L -galactose. Immature berries also accumulated TA in early berry development in co-ordination with up-regulation of a TA biosynthetic gene. In contrast, ripe berries have up-regulated expression of the alternative Asc biosynthetic pathway gene D -galacturonic acid reductase with only residual expression of Smirnoff-Wheeler Asc biosynthetic pathway genes and of the TA biosynthetic gene. The ripening phase was further associated with up-regulation of Asc recycling genes, a secondary phase of increased accumulation of Asc and an increase in the Asc to DHA ratio. We demonstrate strong developmental regulation of Asc biosynthetic, recycling and catabolic genes in grape berries. Integration of the transcript, radiotracer and metabolite data demonstrates that Asc and TA metabolism are developmentally regulated in grapevines resulting in low accumulated levels of the biosynthetic intermediate Asc, and high accumulated levels of the metabolic end-product TA.

Biochemical and cytogenetic biomarkers of pollutant exposure in marine fish (Aldrichetta forsteriValenciennes andSillago schomburgkiiPeters) near industrial and metropolitan centres in S

Publisher: Informa UK Limited

Date: 1999

DOI: 10.1080/135475099230822

Abstract: This project aimed to measure biochemical and cytogenetic biomarkers in marine fish (Aldrichetta forsteri and Sillago schomburgkii) associated with industrial and urban centres in South Australia. These sites were Port Pirie (affected by metal-contaminated outflows), Barker Inlet (adjacent to Metropolitan Adelaide), and Wills Creek (reference site). The biochemical biomarkers included sorbitol dehydrogenase (SDH) and alanine aminotransferase (ALAT) in serum, adenylate levels (ATP, ADP and AMP) and adenylate energy charge (AEC) in gill and liver, and sodium otassium ATPase (Na(+), K(+)-ATPase) in gill. Erythrocyte micronucleus frequency was a marker of cytogenetic effect. Serum enzyme levels were generally higher in fish from Port Pirie and Barker Inlet than in those from Wills Creek, with SDH demonstrating the clearest site-associated differences. Tissue adenylates were consistently lower at Port Pirie than elsewhere, suggesting a greater metabolic strain in fish at this site. AEC in gill and liver were consistently lower at Port Pirie than at Wills Creek, with Barker Inlet generally between these two. The reversed rank order was observed with erythrocyte micronucleus frequencies. Seasonal variations in the biomarkers may be attributed either to seasonal physiological changes in fish or changes in pollutant input levels or compositions. Na(+), K(+)-ATPase did not differ between sites nor seasons in this study. This work shows that biochemical and cytogenetic differences occur in marine fish at specific locations in South Australia. It also shows that of these tests, serum SDH and erythrocyte micronuclei are potentially the most sensitive and reliable biomarkers of pollutants effects on marine fish. The results also suggest that these data may be used as a baseline against which future changes in marine water quality, and their consequent biological effects, can be compared.

Screening of Australian Native Grasses for Rhizoremediation of Aliphatic Hydrocarbon-Contaminated Soil

Publisher: Informa UK Limited

Date: 23-07-2008

DOI: 10.1080/15226510802100465

Abstract: Rhizoremediation involves the breakdown of contaminants in soil resulting from microbial activity that is enhanced in the plant root zone. The objective of this study was to identify Australian native grass species as suitable candidates for rhizoremediation application. Seeds of nine perennial Australian native grasses were sown in soil from a mine site and artificially contaminated with a 60:40 diesel/oil mixture at concentrations of 1% (w/w), 0.5% (w/w), and 0% (control). Seedling emergence was not adversely affected by the presence of hydrocarbon contamination for all but one grass species. Three promising species (Brachiaria decumbens, Cymbopogon ambiguus, and Microlaena stipoides var. Griffin) were assessed for growth characterization in contaminated and uncontaminated soils. The evaluated species survived for 120 days in the contaminated soil and, in some instances, produced considerably more root biomass in the presence of contamination. C. ambiguus showed growth stimulation in the presence of contamination (1% and 0.5% w/w) with significantly increased root biomass production compared with the control (p = 0.0001). B. decumbens and M. stipoides showed tolerance, without adverse growth effects in the presence of diesel/oil at the exposed concentrations. Stimulation of the rhizosphere microbial population that is capable of degrading diesel/oil was found for all of the species tested, using a most probable number method for enumeration. This investigation has identified suitable candidates for further investigation of their rhizoremediation potential.

Detection of glycosyl‐phosphatidylinositol‐anchored proteins on the surface of Nicotiana tabacum protoplasts

Publisher: Wiley

Date: 17-03-1997

DOI: 10.1016/S0014-5793(97)00064-1

Abstract: Glycosyl-phosphatidylinositol (GPI)-anchored plasma membrane proteins have been found to be widespread in eukaryotes and protozoa but have not been reported in higher terrestrial plants. A sensitive biotin-based assay has been used to detect the presence of GPI-anchored proteins on the outer surface of cultured Nicotiana tabacum cells. Six proteins with molecular weights of 92, 84, 60.5, 54.5, 39.5 and 37 kDa were found to move from a Triton X-114 detergent-rich phase to an aqueous phase following incubation with phosphatidylinositol-specific phospholipase C (PtdIns-PLC). The behaviour of these proteins is consistent with the presence of a GPI-anchor. Seven GPI-anchored proteins were also detected on the surface of tobacco leaf protoplasts with molecular weights of 67.5, 62, 39, 33.5, 27, 23 and 15.6 kDa. These data demonstrate the presence of multiple GPI-anchored proteins on the plasma membrane of higher plant cells.

Characterization of Mitochondrial Alternative NAD(P)H Dehydrogenases in Arabidopsis: Intraorganelle Location and Expression

Publisher: Oxford University Press (OUP)

Date: 2006

DOI: 10.1093/PCP/PCI221

Abstract: The intramitochondrial location of putative type II NAD(P)H dehydrogenases (NDs) in Arabidopsis was investigated by measuring the ability of isolated mitochondria to take up precursor proteins generated from cDNAs using an in vitro translation system. The mature proteins of NDA1, NDA2 and NDC1 were judged to be located on the inside of the inner membrane because they were protected from protease added after the mitochondrial outer membrane had been ruptured. In contrast, NDB1, NDB2 and NDB4 were not protected from protease digestion in mitochondria with ruptured outer membranes and were deemed to be located on the outside of the inner membrane. Expression of all ND genes was measured using quantitative reverse transcription-PCR (RT-PCR) to determine transcript abundance, and compared with expression of alternative oxidase, uncoupler proteins and selected components of the oxidative phosphorylation complexes. NDA1 and NDB2 were the most prominently expressed members in a variety of tissues, and were up-regulated in the early daytime in a diurnal manner. Analysis of array data suggested that NDA1 clustered closest to the gene encoding the P-subunit of glycine decarboxylase. Taken together with the diurnal regulation of NDA1 observed here and in other studies, this suggests that NDA1 plays a role in integrating metabolic activities of chloroplasts and mitochondria. NDA2, NDB2 and Aox1a were up-regulated in a coordinated manner under various treatments, potentially forming a complete respiratory chain capable of oxidizing matrix and cytosolic NAD(P)H. NDB1 and NDC1 were down-regulated under the same conditions and may be regarded as housekeeping genes.

Manipulation of alternative oxidase can influence salt tolerance in Arabidopsis thaliana

Publisher: Wiley

Date: 17-11-2009

DOI: 10.1111/J.1399-3054.2009.01305.X

Abstract: The growth and development of plants can be limited by environmental stresses such as salinity. It has been suggested that the non-phosphorylating alternative respiratory pathway in plants, mediated by the NAD(P)H dehydrogenase [NAD(P)H DH] and alternative oxidase (AOX), is important during environmental stresses. The involvement of this alternative pathway in a stress response may be linked to its capacity to uncouple carbon metabolism from adenylate control and/or the minimization of the formation of destructive reactive oxygen species (ROS). Salinity stress is a widespread, adverse environmental stress, which leads to an ionic imbalance, hyperosmotic stress and oxidative stress, the latter being the result of ROS formation. In this study, we show that salinity stress of Arabidopsis thaliana plants resulted in the formation of ROS, increased levels of Na+ in both the shoot and the root and an increase in transcription of Ataox1a, Atndb2 and Atndb4 genes, indicating the formation of an abridged non-phosphorylating electron transport chain in response to salinity stress. Furthermore, plants constitutively over-expressing Ataox1a, with increased AOX capacity, showed lower ROS formation, 30-40% improved growth rates and lower shoot Na+ content compared with controls, when grown under salinity stress conditions. Thus, more active AOX in roots and shoots can improve the salt tolerance of Arabidopsis as defined by its ability to grow more effectively in the presence of NaCl, and maintain lower shoot Na+ content. AOX does have an important role in stress adaptation in plants, and these results provide some validation of the hypothesis that AOX can play a critical role in cell re-programming under salinity stress.

Determining the Methoxypyrazine Biosynthesis Variables Affected by Light Exposure and Crop Level in Cabernet Sauvignon

Publisher: American Society for Enology and Viticulture

Date: 19-08-2013

DOI: 10.5344/AJEV.2013.13070

Alterations in the Mitochondrial Alternative NAD(P)H Dehydrogenase NDB4 Lead to Changes in Mitochondrial Electron Transport Chain Composition, Plant Growth and Response to Oxidative Stress

Publisher: Oxford University Press (OUP)

Date: 09-06-2011

DOI: 10.1093/PCP/PCR073

Abstract: The branched respiratory electron transport chain of plants contains a non-phosphorylating alternative pathway consisting of type II NAD(P)H dehydrogenases on both sides of the inner membrane linked through the ubiquinone pool to an alternative oxidase (AOX). T-DNA and RNA interference (RNAi) were used to reduce gene expression to characterize the external NAD(P)H dehydrogenase NDB4 in Arabidopsis. The ndb4 lines showed different levels of suppression of NDB4 protein, leading to increases in NBD2 and AOX1a mRNA and protein levels in all lines. These changes were associated with lower reactive oxygen species formation and an altered phenotype, including changes in growth rate, root : shoot ratios and leaf area. The general growth pattern for the ndb4 mutants was decreased leaf area early in development (6-15 d) followed by a prompt subsequent increase in leaf area that exceeded the leaf area of the wild type by maturity (the 10-12 rosette stage). This pattern was most evident for the RNAi lines that had increased mitochondrial electron transport capacity. The RNAi lines also exhibited better tolerance to salinity stress, with better growth rates and lower shoot Na⁺ content compared with controls when grown under saline conditions. We hypothesize that these differences reflect the enhanced expression of NDB2 and AOX in the ndb4 mutant plants.

Metal Levels in Seston and Marine Fish Flesh Near Industrial and Metropolitan Centres in South Australia

Publisher: Elsevier BV

Date: 05-2001

DOI: 10.1016/S0025-326X(00)00168-5

Abstract: Port Pirie is the site of the largest lead smelter in the world, depositing 250 t of zinc, and 100 t of lead annually into Spencer Gulf. Barker Inlet is adjacent to metropolitan Adelaide, and receives unknown quantities of urban and industrial discharges. Both areas are sites of major commercial and recreational fisheries, contained within delicately balanced marine wetland ecosystems, comprising large areas of mangrove and seagrass habitats. Aldrichetta forsteri and Sillago schomburgkii are major species within these fisheries and as estuarine-dependent species were chosen for this study as indicator species for the detection and monitoring of pollutant impacts in the nearshore marine ecosystems of South Australia. Seston sediment collectors were deployed at each site and analysed seasonally for the presence of cadmium, lead and copper. Flesh s les from A. forsteri and S. schomburgkii were examined seasonally for the presence of cadmium, lead and copper and the results correlated with levels found in the seston sediment at each site. Metal concentrations were also correlated with a biomarker of genotoxicity measured in the same animals (micronuclei in erythrocytes) that were reported previously. Seston levels of cadmium, lead and copper were highest at Port Pirie, followed by Barker Inlet and were lowest at Wills Creek, with cadmium undetectable at the latter site. Metals in seston varied considerably with season, with generally higher levels in winter s les. In fish flesh, metal levels followed broadly similar trends as for seston. Spearman rank correlations between metals in seston and in flesh were strongly positive. There was also a significant correlation between flesh concentrations of each metal and the frequency of micronuclei in erythrocytes. This study has shown that seston concentration of pollutant metals are high in areas of industrial activity, and that these levels are also reflected in metal content of fish flesh. Mean flesh levels of cadmium and copper did not exceed Australian health based maximum permitted levels of fish for human consumption, whereas flesh levels of lead in fish from Port Pirie and Barker Inlet exceeded these standards in each of the seasons monitored. This may represent a significant dietary source of lead in humans, especially at Port Pirie where human lead exposure from terrestrial sources is important. There may also be the potential for accumulation of metals in residents of metropolitan Adelaide whose diets are high in fish (and/or crustaceans), particularly estuarine-dependent species, such as A. forsteri and S. schomburgkii. The study also showed that a non-specific biomarker of genotoxicity (micronuclei in erythrocytes) is potentially useful as a monitoring technique in fish species to evaluate their exposure and genotoxic responses to pollutants in South Australian waters. These data represent a snapshot of the current situation in this area and may act as background levels against which future improvements or decrements in water quality may be compared.

Selenium increases seed production in Brassica

Publisher: Springer Science and Business Media LLC

Date: 12-11-2009

DOI: 10.1007/S11104-008-9818-7

Comparison of Recombinant Barramundi and Human Insulin-like Growth Factor (IGF)-I in Juvenile Barramundi (Lates calcarifer): In Vivo Metabolic Effects, Association with Circulating IGF-Binding Protein

Publisher: Elsevier BV

Date: 03-2000

DOI: 10.1006/GCEN.1999.7417

Metabolic effects of elevated temperature on organic acid degradation in ripening Vitis vinifera fruit

Publisher: Oxford University Press (OUP)

Date: 09-2014

DOI: 10.1093/JXB/ERU343

Expression of Specific Alleles of Zinc-Finger Transcription Factors, HvSAP8 and HvSAP16, and Corresponding SNP Markers, Are Associated with Drought Tolerance in Barley Populations

Publisher: MDPI AG

Date: 10-11-2021

DOI: 10.3390/IJMS222212156

Abstract: Two genes, HvSAP8 and HvSAP16, encoding Zinc-finger proteins, were identified earlier as active in barley plants. Based on bioinformatics and sequencing analysis, six SNPs were found in the promoter regions of HvSAP8 and one in HvSAP16, among parents of two barley segregating populations, Granal × Baisheshek and Natali × Auksiniai-2. ASQ and Amplifluor markers were developed for HvSAP8 and HvSAP16, one SNP in each gene, and in each of two populations, showing simple Mendelian segregation. Plants of F6 selected breeding lines and parents were evaluated in a soil-based drought screen, revealing differential expression of HvSAP8 and HvSAP16 corresponding with the stress. After almost doubling expression during the early stages of stress, HvSAP8 returned to pre-stress level or was strongly down-regulated in plants with Granal or Baisheshek genotypes, respectively. For HvSAP16 under drought conditions, a high expression level was followed by either a return to original levels or strong down-regulation in plants with Natali or Auksiniai-2 genotypes, respectively. Grain yield in the same breeding lines and parents grown under moderate drought was strongly associated with their HvSAP8 and HvSAP16 genotypes. Additionally, Granal and Natali genotypes with specific alleles at HvSAP8 and HvSAP16 were associated with improved performance under drought via higher 1000 grain weight and more shoots per plant, respectively.

An aldo-keto reductase with 2-keto-l-gulonate reductase activity functions in l-tartaric acid biosynthesis from vitamin C in Vitis vinifera

Publisher: Elsevier BV

Date: 11-2019

DOI: 10.1074/JBC.RA119.010196

A method for determination of fruit-derived ascorbic, tartaric, oxalic and malic acids, and its application to the study of ascorbic acid catabolism in grapevines

Publisher: Hindawi Limited

Date: 10-2009

DOI: 10.1111/J.1755-0238.2009.00062.X

Identification of AtNDI1, an Internal Non-Phosphorylating NAD(P)H Dehydrogenase in Arabidopsis Mitochondria

Publisher: Oxford University Press (OUP)

Date: 12-2003

DOI: 10.1104/PP.103.029363

Abstract: Plant mitochondria contain non-phosphorylating NAD(P)H dehydrogenases (DHs) that are not found in animal mitochondria. The physiological function, substrate specificity, and location of enzymes within this family have yet to be conclusively determined. We have linked genome sequence information to protein and biochemical data to identify that At1g07180 (SwissProt Q8GWA1) from the Arabidopsis Genome Initiative database encodes AtNDI1, an internal NAD(P)H DH in Arabidopsis mitochondria. Three lines of evidence are presented: (a) The predicted protein sequence of AtNDI1 has high homology with other designated NAD(P)H DHs from microorganisms, (b) the capacity for matrix NAD(P)H oxidation via the rotenone-insensitive pathway is significantly reduced in the Atndi1 mutant plant line, and (c) the in vitro translation product of AtNDI1 is imported into isolated mitochondria and located on the inside of the inner membrane.

Organization and Regulation of Mitochondrial Respiration in Plants

Publisher: Annual Reviews

Date: 02-06-2011

DOI: 10.1146/ANNUREV-ARPLANT-042110-103857

Abstract: Mitochondrial respiration in plants provides energy for biosynthesis, and its balance with photosynthesis determines the rate of plant biomass accumulation. We describe recent advances in our understanding of the mitochondrial respiratory machinery of cells, including the presence of a classical oxidative phosphorylation system linked to the cytosol by transporters, discussed alongside nonphosphorylating (and, therefore, non-energy conserving) bypasses that alter the efficiency of ATP synthesis and play a role in oxidative stress responses in plants. We consider respiratory regulation in the context of the contrasting roles mitochondria play in different tissues, from photosynthetic leaves to nutrient-acquiring roots. We focus on the molecular nature of this regulation at transcriptional and post-transcriptional levels that allow the respiratory apparatus of plants to help shape organ development and the response of plants to environmental stress. We highlight the challenges for future research considering spatial and temporal changes of respiration in response to changing climatic conditions.

Early Flowering as a Drought Escape Mechanism in Plants: How Can It Aid Wheat Production?

Publisher: Frontiers Media SA

Date: 17-11-2017

DOI: 10.3389/FPLS.2017.01950

Erratum to: Two O-methyltransferases involved in the biosynthesis of methoxypyrazines: grape-derived aroma compounds important to wine flavour

Publisher: Springer Science and Business Media LLC

Date: 08-02-2013

DOI: 10.1007/S11103-013-0012-9

Corrigendum to: Expression Level of the DREB2-TypeGene, Identified with Amplifluor SNP Markers, Correlates with Performance, and Tolerance to Dehydration in Bread Wheat Cultivars from Northern Kazakhstan (Front. Plant Sci, (2016) 7, (1736), 10.3389/fpls.2016.01736)

Publisher: Frontiers Media SA

Date: 07-09-2017

DOI: 10.3389/FPLS.2017.01571

Energy costs of salinity tolerance in crop plants

Publisher: Wiley

Date: 29-11-2019

DOI: 10.1111/NPH.15555

Stable Isotope Analysis Of Environmental And Physiological Samples

Start Date: 2012

End Date: 2012

Funder: Australian Research Council

Engineering The Plant Mitochondrial Electron Transport Chain To Tolerate Environmental Stress

Start Date: 2014

End Date: 2016

Funder: Australian Research Council

South Australian High Throughput Screening Facility

Start Date: 2015

End Date: 2015

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE110100177

Start Date: 2011

End Date: 12-2011

Amount: $150,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0560102

Start Date: 2005

End Date: 12-2007

Amount: $215,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE120100054

Start Date: 01-2012

End Date: 12-2013

Amount: $420,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP140103090

Start Date: 2014

End Date: 12-2018

Amount: $387,095.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0209247

Start Date: 2002

End Date: 12-2005

Amount: $168,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0990196

Start Date: 03-2010

End Date: 12-2016

Amount: $78,420.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE150100203

Start Date: 06-2015

End Date: 12-2016

Amount: $860,000.00

Funder: Australian Research Council