ORCID Profile
0000-0003-4871-9260
Current Organisations
Eidgenössische Technische Hochschule ETH
,
University of Bristol
,
University of Adelaide
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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 Developmental and Reproductive Biology | Plant Cell and Molecular Biology | Plant Biology | Plant Physiology | Crop and Pasture Production | Horticultural Crop Growth and Development | Invertebrate Biology | Horticultural Production | Plant Protection (Pests, Diseases And Weeds) |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Biological Sciences | Horticultural Crops not elsewhere classified | Industrial Crops not elsewhere classified | Field crops | Barley | Control of pests and exotic species | Forestry not elsewhere classified
Related Links
Publications
Strigolactone acts downstream of auxin to regulate bud outgrowth in pea and arabidopsis
Publisher: Oxford University Press (OUP)
Date: 25-03-2009
Abstract: During the last century, two key hypotheses have been proposed to explain apical dominance in plants: auxin promotes the production of a second messenger that moves up into buds to repress their outgrowth, and auxin saturation in the stem inhibits auxin transport from buds, thereby inhibiting bud outgrowth. The recent discovery of strigolactone as the novel shoot-branching inhibitor allowed us to test its mode of action in relation to these hypotheses. We found that exogenously applied strigolactone inhibited bud outgrowth in pea (Pisum sativum) even when auxin was depleted after decapitation. We also found that strigolactone application reduced branching in Arabidopsis (Arabidopsis thaliana) auxin response mutants, suggesting that auxin may act through strigolactones to facilitate apical dominance. Moreover, strigolactone application to tiny buds of mutant or decapitated pea plants rapidly stopped outgrowth, in contrast to applying N-1-naphthylphthalamic acid (NPA), an auxin transport inhibitor, which significantly slowed growth only after several days. Whereas strigolactone or NPA applied to growing buds reduced bud length, only NPA blocked auxin transport in the bud. Wild-type and strigolactone biosynthesis mutant pea and Arabidopsis shoots were capable of instantly transporting additional amounts of auxin in excess of endogenous levels, contrary to predictions of auxin transport models. These data suggest that strigolactone does not act primarily by affecting auxin transport from buds. Rather, the primary repressor of bud outgrowth appears to be the auxin-dependent production of strigolactones.
The trihelix family of transcription factors - light, stress and development
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.TPLANTS.2011.12.002
Abstract: GT factors are the founding members of the trihelix transcription factor family. They bind GT elements in light regulated genes, and their nature was uncovered in a burst of activity in the 1990s. Study of the trihelix family then slowed. However, interest is now re-awakening. Genomic studies have revealed 30 members of this family in Arabidopsis and 31 in rice, falling into five clades. Newly discovered functions involve responses to salt and pathogen stresses, the development of perianth organs, trichomes, stomata and the seed abscission layer, and the regulation of late embryogenesis. Thus the time is ripe for a review of the genomic and functional information now emerging for this neglected family.
In situ hybridization technique for mRNA detection in whole mount Arabidopsis samples
Publisher: Springer Science and Business Media LLC
Date: 11-2006
Abstract: High throughput microarray transcription analyses provide us with the expression profiles for large amounts of plant genes. However, their tissue and cellular resolution is limited. Thus, for detailed functional analysis, it is still necessary to examine the expression pattern of selected candidate genes at a cellular level. Here, we present an in situ mRNA hybridization method that is routinely used for the analysis of plant gene expression patterns. The protocol is optimized for whole mount mRNA localizations in Arabidopsis seedling tissues including embryos, roots, hypocotyls and young primary leaves. It can also be used for comparable tissues in other species. Part of the protocol can also be automated and performed by a liquid handling robot. Here we present a detailed protocol, recommended controls and troubleshooting, along with ex les of several applications. The total time to carry out the entire procedure is approximately 7 d, depending on the tissue used.
Strigolactone inhibition of shoot branching
Publisher: Springer Science and Business Media LLC
Date: 10-08-2008
DOI: 10.1038/NATURE07271
Abstract: A carotenoid-derived hormonal signal that inhibits shoot branching in plants has long escaped identification. Strigolactones are compounds thought to be derived from carotenoids and are known to trigger the germination of parasitic plant seeds and stimulate symbiotic fungi. Here we present evidence that carotenoid cleavage dioxygenase 8 shoot branching mutants of pea are strigolactone deficient and that strigolactone application restores the wild-type branching phenotype to ccd8 mutants. Moreover, we show that other branching mutants previously characterized as lacking a response to the branching inhibition signal also lack strigolactone response, and are not deficient in strigolactones. These responses are conserved in Arabidopsis. In agreement with the expected properties of the hormonal signal, exogenous strigolactone can be transported in shoots and act at low concentrations. We suggest that endogenous strigolactones or related compounds inhibit shoot branching in plants. Furthermore, ccd8 mutants demonstrate the erse effects of strigolactones in shoot branching, mycorrhizal symbiosis and parasitic weed interaction.
Plant Architecture: The Long and the Short of Branching in Potato
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.CUB.2015.06.066
Abstract: A new report details the interaction between two isoforms of an important BRANCHED1 (BRC1) transcription factor gene in potato. The regular long form inhibits lateral branching, like BRC1 in other species, but a modified protein that originates from alternative BRC1 splicing inhibits the long form and promotes lateral branching.
Phloem Transport of the Receptor DWARF14 Protein Is Required for Full Function of Strigolactones
Publisher: Oxford University Press (OUP)
Date: 26-09-2016
DOI: 10.1104/PP.16.01212
Hydroxyl carlactone derivatives are predominant strigolactones in Arabidopsis
Publisher: Wiley
Date: 05-2020
DOI: 10.1002/PLD3.219
Spatiotemporal asymmetric auxin distribution: a means to coordinate plant development
Publisher: Springer Science and Business Media LLC
Date: 29-09-2006
DOI: 10.1007/S00018-006-6116-5
Abstract: The plant hormone auxin plays crucial roles in regulating plant growth development, including embryo and root patterning, organ formation, vascular tissue differentiation and growth responses to environmental stimuli. Asymmetric auxin distribution patterns have been observed within tissues, and these so-called auxin gradients change dynamically during different developmental processes. Most auxin is synthesized in the shoot and distributed directionally throughout the plant. This polar auxin transport is mediated by auxin influx and efflux facilitators, whose subcellular polar localizations guide the direction of auxin flow. The polar localization of PIN auxin efflux carriers changes in response to developmental and external cues in order to channel auxin flow in a regulated manner for organized growth. Auxin itself modulates the expression and subcellular localization of PIN proteins, contributing to a complex pattern of feedback regulation. Here we review the available information mainly from studies of a model plant, Arabidopsis thaliana, on the generation of auxin gradients, the regulation of polar auxin transport and further downstream cellular events.
Strigolactones inhibit auxin feedback on PIN-dependent auxin transport canalization
Publisher: Springer Science and Business Media LLC
Date: 14-07-2020
DOI: 10.1038/S41467-020-17252-Y
Abstract: Directional transport of the phytohormone auxin is a versatile, plant-specific mechanism regulating many aspects of plant development. The recently identified plant hormones, strigolactones (SLs), are implicated in many plant traits among others, they modify the phenotypic output of PIN-FORMED (PIN) auxin transporters for fine-tuning of growth and developmental responses. Here, we show in pea and Arabidopsis that SLs target processes dependent on the canalization of auxin flow, which involves auxin feedback on PIN subcellular distribution. D14 receptor- and MAX2 F-box-mediated SL signaling inhibits the formation of auxin-conducting channels after wounding or from artificial auxin sources, during vasculature de novo formation and regeneration. At the cellular level, SLs interfere with auxin effects on PIN polar targeting, constitutive PIN trafficking as well as clathrin-mediated endocytosis. Our results identify a non-transcriptional mechanism of SL action, uncoupling auxin feedback on PIN polarity and trafficking, thereby regulating vascular tissue formation and regeneration.
Lateral branching oxidoreductase acts in the final stages of strigolactone biosynthesis in Arabidopsis
Publisher: Proceedings of the National Academy of Sciences
Date: 18-05-2016
Abstract: Strigolactone hormones regulate many plant growth and developmental processes and are particularly important in regulating growth in response to nonoptimal conditions. Plants produce a range of bioactive strigolactone-like compounds, suggesting that the biosynthesis pathway is complex. Despite this complexity, only one type of enzyme, the MORE AXILLARY GROWTH1 (MAX1) cytochrome P450, has been attributed to the ersity of strigolactones. Using transcriptomics and reverse genetics, we discovered a previously uncharacterized gene that encodes a 2-oxoglutarate and Fe(II)-dependent dioxygenase involved in strigolactone production downstream of MAX1. Studies with the corresponding mutant have shown that previously identified strigolactone-type compounds in Arabidopsis are not the major strigolactone-type shoot branching hormone in this model species.
Homozygous TAF8 mutation in a patient with intellectual disability results in undetectable TAF8 protein, but preserved RNA polymerase II transcription
Publisher: Oxford University Press (OUP)
Date: 10-04-2018
DOI: 10.1093/HMG/DDY126
Inositol Trisphosphate-Induced Ca2+ Signaling Modulates Auxin Transport and PIN Polarity
Publisher: Elsevier BV
Date: 06-2011
DOI: 10.1016/J.DEVCEL.2011.05.013
Abstract: The phytohormone auxin is an important determinant of plant development. Directional auxin flow within tissues depends on polar localization of PIN auxin transporters. To explore regulation of PIN-mediated auxin transport, we screened for suppressors of PIN1 overexpression (supo) and identified an inositol polyphosphate 1-phosphatase mutant (supo1), with elevated inositol trisphosphate (InsP(3)) and cytosolic Ca(2+) levels. Pharmacological and genetic increases in InsP(3) or Ca(2+) levels also suppressed the PIN1 gain-of-function phenotypes and caused defects in basal PIN localization, auxin transport and auxin-mediated development. In contrast, the reductions in InsP(3) levels and Ca(2+) signaling antagonized the effects of the supo1 mutation and disrupted preferentially apical PIN localization. InsP(3) and Ca(2+) are evolutionarily conserved second messengers involved in various cellular functions, particularly stress responses. Our findings implicate them as modifiers of cell polarity and polar auxin transport, and highlight a potential integration point through which Ca(2+) signaling-related stimuli could influence auxin-mediated development.
Protocol for a block randomised controlled trial of an intervention to improve heart failure care.
Publisher: RCN Publishing Ltd.
Date: 21-03-2016
Abstract: To describe the design of a randomised controlled trial conducted to evaluate a culturally tailored, nurse-led educational intervention. Self-care strategies are critical to improving health outcomes in heart failure. The family unit is crucial in collectivist cultures, but little is known about involving the family in the self-care of patients with heart failure. Involving the family in the self-care of heart failure is a novel approach. To the authors' knowledge, no one has evaluated it using a randomised controlled trial. A valid comparison of outcomes between the control group and the intervention group involved in the study was provided in this trial. The chosen design, randomised controlled trial, enabled the assessment of the intervention. The application of a family self-care intervention in a collectivist culture was shown to improve clinical and quality outcomes of patients with heart failure. Considering the in idual and the community needs is vital in improving these outcomes.
Plasticity of bud outgrowth varies at cauline and rosette nodes in Arabidopsis thaliana
Publisher: Oxford University Press (OUP)
Date: 17-12-2021
Abstract: Shoot branching is a complex mechanism in which secondary shoots grow from buds that are initiated from meristems established in leaf axils. The model plant Arabidopsis (Arabidopsis thaliana) has a rosette leaf growth pattern in the vegetative stage. After flowering initiation, the main stem elongates with the top leaf primordia developing into cauline leaves. Meristems in Arabidopsis initiate in the axils of rosette or cauline leaves, giving rise to rosette or cauline buds, respectively. Plasticity in the process of shoot branching is regulated by resource and nutrient availability as well as by plant hormones. However, few studies have attempted to test whether cauline and rosette branching are subject to the same plasticity. Here, we addressed this question by phenotyping cauline and rosette branching in three Arabidopsis ecotypes and several Arabidopsis mutants with varied shoot architectures. Our results showed no negative correlation between cauline and rosette branch numbers in Arabidopsis, demonstrating that there is no tradeoff between cauline and rosette bud outgrowth. Through investigation of the altered branching pattern of flowering pathway mutants and Arabidopsis ecotypes grown in various photoperiods and light regimes, we further elucidated that the number of cauline branches is closely related to flowering time. The number of rosette branches has an enormous plasticity compared with cauline branches and is influenced by genetic background, flowering time, light intensity, and temperature. Our data reveal different levels of plasticity in the regulation of branching at rosette and cauline nodes, and promote a framework for future branching analyses.
Strigolactone Inhibition of Branching Independent of Polar Auxin Transport
Publisher: Oxford University Press (OUP)
Date: 25-06-2015
DOI: 10.1104/PP.15.00014
Strigolactones, how are they synthesized to regulate plant growth and development?
Publisher: Elsevier BV
Date: 10-2021
Initial bud outgrowth occurs independent of Auxin flow from out of buds
Publisher: Oxford University Press (OUP)
Date: 07-11-2019
DOI: 10.1104/PP.18.00519
How do brassinosteroids fit in bud outgrowth models?
Publisher: Oxford University Press (OUP)
Date: 17-10-2023
DOI: 10.1093/JXB/ERAD394
Efficient production of a mature and functional gamma secretase protease.
Publisher: Springer Science and Business Media LLC
Date: 27-08-2018
DOI: 10.1038/S41598-018-30788-W
Abstract: Baculoviral protein expression in insect cells has been previously used to generate large quantities of a protein of interest for subsequent use in biochemical and structural analyses. The MultiBac baculovirus protein expression system has enabled, the use of a single baculovirus to reconstitute a protein complex of interest, resulting in a larger protein yield. Using this system, we aimed to reconstruct the gamma (γ)-secretase complex, a multiprotein enzyme complex essential for the production of amyloid-β (Aβ) protein. A MultiBac vector containing all components of the γ-secretase complex was generated and expression was observed for all components. The complex was active in processing APP and Notch derived γ-secretase substrates and proteolysis could be inhibited with γ-secretase inhibitors, confirming specificity of the recombinant γ-secretase enzyme. Finally, affinity purification was used to purify an active recombinant γ-secretase complex. In this study we demonstrated that the MultiBac protein expression system can be used to generate an active γ-secretase complex and provides a new tool to study γ-secretase enzyme and its variants.
Different plasticity of bud outgrowth at cauline and rosette nodes in Arabidopsis thaliana
Publisher: Cold Spring Harbor Laboratory
Date: 27-09-2021
DOI: 10.1101/2021.09.26.461886
Abstract: Shoot branching is a complex mechanism in which secondary shoots grow from buds that are initiated from meristems established in leaf axils. The model plant Arabidopsis thaliana has a rosette leaf growth pattern in the vegetative stage. After flowering initiation, the main stem starts to elongate with the top leaf primordia developing into cauline leaves. Meristems in arabidopsis are initiated in the axils of rosette or cauline leaves, giving rise to rosette or cauline buds, respectively. Plasticity in the process of shoot branching is regulated by resource and nutrient availability as well as by plant hormones. However, few studies have attempted to test whether cauline and rosette branching are subject to the same plasticity. Here, we addressed this question by phenotyping cauline and rosette branching in three arabidopsis ecotypes and several arabidopsis mutants with varied shoot architectures. Our results show that there is no negative correlation between cauline and rosette branch numbers in arabidopsis, demonstrating that there is no trade-off between cauline and rosette bud outgrowth. Through investigation of the altered branching pattern of flowering pathway mutants and arabidopsis ecotypes grown in various photoperiods and light regimes, we further elucidated that the number of cauline branches is closely related to flowering time. The number or rosette branches has an enormous plasticity compared with cauline branches and is influenced by genetic background, flowering time, light intensity and temperature. Our data reveal different plasticity in the regulation of branching at rosette and cauline nodes and promote a framework for future branching analyses. Different plasticity of branching at cauline and rosette nodes of arabidopsis is revealed through detailed correlative analyses of branching under varied genetic and environmental contexts.
Strigolactones Are Involved in Root Response to Low Phosphate Conditions in Arabidopsis
Publisher: Oxford University Press (OUP)
Date: 11-09-2012
Abstract: Strigolactones (SLs) are plant hormones that suppress lateral shoot branching, and act to regulate root hair elongation and lateral root formation. Here, we show that SLs are regulators of plant perception of or response to low inorganic phosphate (Pi) conditions. This regulation is mediated by MORE AXILLARY GROWTH2 (MAX2) and correlated with transcriptional induction of the auxin receptor TRANSPORT INHIBITOR RESPONSE1 (TIR1). Mutants of SL signaling (max2-1) or biosynthesis (max4-1) showed reduced response to low Pi conditions relative to the wild type. In max4-1, but not max2-1, the reduction in response to low Pi was compensated by the application of a synthetic strigolactone GR24. Moreover, AbamineSG, which decreases SL levels in plants, reduced the response to low Pi in the wild type, but not in SL-signaling or biosynthesis mutants. In accordance with the reduced response of max2-1 to low Pi relative to the wild type, several phosphate-starvation response and phosphate-transporter genes displayed reduced induction in max2-1, even though Pi content in max2-1 and the wild type were similar. Auxin, but not ethylene, was sufficient to compensate for the reduced max2-1 response to low Pi conditions. Moreover, the expression level of TIR1 was induced under low Pi conditions in the wild type, but not in max2-1. Accordingly, the tir1-1 mutant showed a transient reduction in root hair density in comparison with the wild type under low Pi conditions. Therefore, we suggest that the response of plants to low Pi is regulated by SLs this regulation is transmitted via the MAX2 component of SL signaling and is correlated with transcriptional induction of the TIR1 auxin receptor.
In situ hybridization for mRNA detection in Arabidopsis tissue sections
Publisher: Springer Science and Business Media LLC
Date: 08-2006
Abstract: Plant biology is currently confronted with an overflow of expression profile data provided by high-throughput microarray transcription analyses. However, the tissue and cellular resolution of these techniques is limited. Thus, it is still necessary to examine the expression pattern of selected candidate genes at a cellular level. Here we present an in situ mRNA hybridization method that is routinely used in the analysis of gene expression patterns. The protocol is optimized for mRNA localizations in sectioned tissue of Arabidopsis seedlings including embryos, roots, hypocotyls, young primary leaves and flowers. The detailed protocol, recommended controls and troubleshooting are presented along with ex les of application. The total time for the process is 10 days.
Binding or Hydrolysis? How Does the Strigolactone Receptor Work?
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.TPLANTS.2019.05.001
Abstract: The strigolactone (SL) receptor in plants is unusual in that it both binds and hydrolyses SL molecules. Landmark studies had proposed that a product of hydrolysis irreversibly binds the receptor and then activates signalling. However, recent breakthrough articles (Seto et al. Nat. Commun. 2019 :191 and Shabek et al. Nature 2018 :652-656) have revealed a new model based on inhibition of hydrolysis by protein conformation.
Pathogen-sugar interactions revealed by universal saturation transfer analysis
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-07-2022
Abstract: Many pathogens exploit host cell-surface glycans. However, precise analyses of glycan ligands binding with heavily modified pathogen proteins can be confounded by overlapping sugar signals and/or compounded with known experimental constraints. Universal saturation transfer analysis (uSTA) builds on existing nuclear magnetic resonance spectroscopy to provide an automated workflow for quantitating protein-ligand interactions. uSTA reveals that early-pandemic, B-origin-lineage severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike trimer binds sialoside sugars in an “end-on” manner. uSTA-guided modeling and a high-resolution cryo–electron microscopy structure implicate the spike N-terminal domain (NTD) and confirm end-on binding. This finding rationalizes the effect of NTD mutations that abolish sugar binding in SARS-CoV-2 variants of concern. Together with genetic variance analyses in early pandemic patient cohorts, this binding implicates a sialylated polylactosamine motif found on tetraantennary N-linked glycoproteins deep in the human lung as potentially relevant to virulence and/or zoonosis.
The Strigolactone Pathway Is a Target for Modifying Crop Shoot Architecture and Yield
Publisher: MDPI AG
Date: 08-01-2023
Abstract: Due to their sessile nature, plants have developed the ability to adapt their architecture in response to their environment. Branching is an integral component of plant architecture, where hormonal signals tightly regulate bud outgrowth. Strigolactones (SLs), being a novel class of phytohormone, are known to play a key role in branching decisions, where they act as a negative regulator of bud outgrowth. They can achieve this by modulating polar auxin transport to interrupt auxin canalisation, and independently of auxin by acting directly within buds by promoting the key branching inhibitor TEOSINTE BRANCHED1. Buds will grow out in optimal conditions however, when conditions are sub-optimal, SL levels increase to restrict branching. This can be a problem in agricultural applications, as reductions in branching can have deleterious effects on crop yield. Variations in promoter elements of key SL-related genes, such as IDEAL PLANT ARCHITECTURE1, have been identified to promote a phenotype with enhanced yield performance. In this review we highlight how this knowledge can be applied using new technologies to develop new genetic variants for improving crop shoot architecture and yield.
The Arabidopsis ortholog of rice DWARF27 acts upstream of MAX1 in the control of plant development by strigolactones
Publisher: Oxford University Press (OUP)
Date: 22-05-2012
Abstract: Strigolactones (SLs) are carotenoid-derived plant hormones that regulate shoot branching, secondary growth, root development, and responses to soil phosphate. In Arabidopsis (Arabidopsis thaliana), SL biosynthesis requires the sequential action of two carotenoid cleavage dioxygenases, MORE AXILLARY GROWTH3 (MAX3) and MAX4, followed by a cytochrome P450, MAX1. In rice (Oryza sativa), the plastid-localized protein DWARF27 (OsD27) is also necessary for SL biosynthesis, but the equivalent gene in Arabidopsis has not been identified. Here, we use phylogenetic analysis of D27-like sequences from photosynthetic organisms to identify AtD27, the likely Arabidopsis ortholog of OsD27. Using reverse genetics, we show that AtD27 is required for the inhibition of secondary bud outgrowth and that exogenous application of the synthetic SL GR24 can rescue the increased branching phenotype of an Atd27 mutant. Furthermore, we use grafting to demonstrate that AtD27 operates on a nonmobile precursor upstream of MAX1 in the SL biosynthesis pathway. Consistent with the plastid localization of OsD27, we also show that AtD27 possesses a functional plastid transit peptide. We demonstrate that AtD27 transcripts are subject to both local feedback and auxin-dependent signals, albeit to a lesser extent than MAX3 and MAX4, suggesting that early steps in SL biosynthesis are coregulated at the transcriptional level. By identifying an additional component of the canonical SL biosynthesis pathway in Arabidopsis, we provide a new tool to investigate the regulation of shoot branching and other SL-dependent developmental processes.
Polar Auxin Transport and Asymmetric Auxin Distribution
Publisher: BioOne
Date: 2007
DOI: 10.1199/TAB.0108
Strigolactone signaling is required for auxin-dependent stimulation of secondary growth in plants
Publisher: Proceedings of the National Academy of Sciences
Date: 28-11-2011
Abstract: Long distance cell-to-cell communication is critical for the development of multicellular organisms. In this respect, plants are especially demanding as they constantly integrate environmental inputs to adjust growth processes to different conditions. One ex le is thickening of shoots and roots, also designated as secondary growth. Secondary growth is mediated by the vascular cambium, a stem cell-like tissue whose cell-proliferating activity is regulated over a long distance by the plant hormone auxin. How auxin signaling is integrated at the level of cambium cells and how cambium activity is coordinated with other growth processes are largely unknown. Here, we provide physiological, genetic, and pharmacological evidence that strigolactones (SLs), a group of plant hormones recently described to be involved in the repression of shoot branching, positively regulate cambial activity and that this function is conserved among species. We show that SL signaling in the vascular cambium itself is sufficient for cambium stimulation and that it interacts strongly with the auxin signaling pathway. Our results provide a model of how auxin-based long-distance signaling is translated into cambium activity and suggest that SLs act as general modulators of plant growth forms linking the control of shoot branching with the thickening of stems and roots.
Strigolactones and Shoot Branching: What Is the Real Hormone and How Does It Work?
Publisher: Oxford University Press (OUP)
Date: 08-2023
DOI: 10.1093/PCP/PCAD088
Abstract: There have been substantial advances in our understanding of many aspects of strigolactone regulation of branching since the discovery of strigolactones as phytohormones. These include further insights into the network of phytohormones and other signals that regulate branching, as well as deep insights into strigolactone biosynthesis, metabolism, transport, perception and downstream signaling. In this review, we provide an update on recent advances in our understanding of how the strigolactone pathway co-ordinately and dynamically regulates bud outgrowth and pose some important outstanding questions that are yet to be resolved.
Polar PIN Localization Directs Auxin Flow in Plants
Publisher: American Association for the Advancement of Science (AAAS)
Date: 12-05-2006
Abstract: Polar flow of the phytohormone auxin requires plasma membrane‐associated PIN proteins and underlies multiple developmental processes in plants. Here we address the importance of the polarity of subcellular PIN localization for the directionality of auxin transport in Arabidopsis thaliana. Expression of different PINs in the root epidermis revealed the importance of PIN polar positions for directional auxin flow and root gravitropic growth. Interfering with sequence-embedded polarity signals directly demonstrates that PIN polarity is a primary factor in determining the direction of auxin flow in meristematic tissues. This finding provides a crucial piece in the puzzle of how auxin flow can be redirected via rapid changes in PIN polarity.
The Nucleosome Remodeling and Deacetylase Complex NuRD Is Built from Preformed Catalytically Active Sub-modules
Publisher: Elsevier BV
Date: 07-2016
Strigolactones: discovery of the elusive shoot branching hormone
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.TPLANTS.2009.04.003
Abstract: The control of axillary bud outgrowth involves a network of hormonal signals and feedback regulation. A repressor of bud outgrowth that is central to the story has been missing since it was first postulated more than 70 years ago. This hormone moves upward in plant stems and can act as a long-distance messenger for auxin. Strigolactones, previously known as carotenoid-derived signals exuded from roots, fit the role of this elusive hormone. The discovery of branching inhibition by strigolactones will help solve many confusing aspects of branch control, including interactions with other signals, and is a great step forward toward uncovering the links between environment, genetics and plant form.
Identification of new potential downstream transcriptional targets of the strigolactone pathway including glucosinolate biosynthesis
Publisher: Wiley
Date: 03-2023
DOI: 10.1002/PLD3.486
Abstract: Strigolactones regulate shoot branching and many aspects of plant growth, development, and allelopathy. Strigolactones are often discussed alongside auxin because they work together to inhibit shoot branching. However, the roles and mechanisms of strigolactones and how they act independently of auxin are still elusive. Additionally, there is still much in general to be discovered about the network of molecular regulators and their interactions in response to strigolactones. Here, we conducted an experiment in Arabidopsis with physiological treatments and strigolactone mutants to determine transcriptional pathways associated with strigolactones. The three physiological treatments included shoot tip removal with and without auxin treatment and treatment of intact plants with the auxin transport inhibitor, N ‐1‐naphthylphthalamic acid (NPA). We identified the glucosinolate biosynthesis pathway as being upregulated across strigolactone mutants indicating strigolactone–glucosinolate crosstalk. Additionally, strigolactone application cannot restore the highly branched phenotype observed in glucosinolate biosynthesis mutants, placing glucosinolate biosynthesis downstream of strigolactone biosynthesis. Oxidative stress genes were enriched across the experiment suggesting that this process is mediated through multiple hormones. Here, we also provide evidence supporting non‐auxin‐mediated, negative feedback on strigolactone biosynthesis. Increases in strigolactone biosynthesis gene expression seen in strigolactone mutants could not be fully restored by auxin. By contrast, auxin could fully restore auxin‐responsive gene expression increases, but not sugar signaling‐related gene expression. Our data also point to alternative roles of the strigolactone biosynthesis genes and potential new signaling functions of strigolactone precursors. In this study, we identify a strigolactone‐specific regulation of glucosinolate biosynthesis genes indicating that the two are linked and may work together in regulating stress and shoot branching responses in Arabidopsis. Additionally, we provide evidence for non‐auxin‐mediated feedback on strigolactone biosynthesis and discuss this in the context of sugar signaling.
Interlocking Disulfides in Circular Proteins: Toward Efficient Oxidative Folding of Cyclotides
Publisher: Mary Ann Liebert Inc
Date: 2011
Abstract: Cyclotides are ultrastable plant proteins characterized by the presence of a cyclic amide backbone and three disulfide bonds that form a cystine knot. Because of their extreme stability, there has been significant interest in developing these molecules as a drug design scaffold. For this potential to be realized, efficient methods for the synthesis and oxidative folding of cyclotides need to be developed, yet we currently have only a basic understanding of the folding mechanism and the factors influencing this process. In this study, we determine the major factors influencing oxidative folding of the different subfamilies of cyclotides. The folding of all the cyclotides examined was heavily influenced by the concentration of redox reagents, with the folding rate and final yield of the native isomer greatly enhanced by high concentrations of oxidized glutathione. Addition of hydrophobic solvents to the buffer also enhanced the folding rates and appeared to alter the folding pathway. Significant deamidation and isoaspartate formation were seen when oxidation conditions were conducive to slow folding. The identification of factors that influence the folding and degradation pathways of cyclotides will facilitate the development of folding screens and optimized conditions for producing cyclotides and grafted analogs as stable peptide-based therapeutics.
Diverse Roles of MAX1 Homologues in Rice
Publisher: MDPI AG
Date: 13-11-2020
Abstract: Cytochrome P450 enzymes encoded by MORE AXILLARY GROWTH1 (MAX1)-like genes produce most of the structural ersity of strigolactones during the final steps of strigolactone biosynthesis. The erse copies of MAX1 in Oryza sativa provide a resource to investigate why plants produce such a wide range of strigolactones. Here we performed in silico analyses of transcription factors and microRNAs that may regulate each rice MAX1, and compared the results with available data about MAX1 expression profiles and genes co-expressed with MAX1 genes. Data suggest that distinct mechanisms regulate the expression of each MAX1. Moreover, there may be novel functions for MAX1 homologues, such as the regulation of flower development or responses to heavy metals. In addition, in idual MAX1s could be involved in specific functions, such as the regulation of seed development or wax synthesis in rice. Our analysis reveals potential new avenues of strigolactone research that may otherwise not be obvious.
Patterns of Variation Within Self-Incompatibility Loci
Publisher: Oxford University Press (OUP)
Date: 27-06-2003
Diverse roles of strigolactones in plant development
Publisher: Elsevier BV
Date: 2013
DOI: 10.1093/MP/SSS130
Abstract: With the discovery of strigolactones as root exudate signals that trigger parasitic weed seed germination, and then as a branching inhibitor and plant hormone, the next phase of strigolactone research has quickly revealed this hormone class as a major player in optimizing plant growth and development. From the early stages of plant evolution, it seems that strigolactones were involved in enabling plants to modify growth in order to gain advantage in competition with neighboring organisms for limited resources. For ex le, a moss plant can alter its growth in response to strigolactones emanating from a neighbor. Within a higher plant, strigolactones appear to be involved in controlling the balance of resource distribution via strategic modification of growth and development. Most notably, higher plants that encounter phosphate deficiency increase strigolactone production, which changes root growth and promotes fungal symbiosis to enhance phosphate intake. The shoot also changes by channeling resources away from unessential leaves and branches and into the main stem and root system. This hormonal response is a key adaption that radically alters whole-plant architecture in order to optimize growth and development under erse environmental conditions.
The ability of plants to produce strigolactones affects rhizosphere community composition of fungi but not bacteria
Publisher: Elsevier BV
Date: 03-2019
Live-cell three-dimensional single-molecule tracking reveals modulation of enhancer dynamics by NuRD
Publisher: Springer Science and Business Media LLC
Date: 28-09-2023
Cellular and Molecular Requirements for Polar PIN Targeting and Transcytosis in Plants
Publisher: Elsevier BV
Date: 11-2008
DOI: 10.1093/MP/SSN062
Abstract: The polar, sub-cellular localization of PIN auxin efflux carriers determines the direction of intercellular auxin flow, thus defining the spatial aspect of auxin signalling. Dynamic, transcytosis-like relocalizations of PIN proteins occur in response to external and internal signals, integrating these signals into changes in auxin distribution. Here, we examine the cellular and molecular mechanisms of polar PIN delivery and transcytosis. The mechanisms of the ARF-GEF-dependent polar targeting and transcytosis are well conserved and show little variations among erse Arabidopsis ecotypes consistent with their fundamental importance in regulating plant development. At the cellular level, we refine previous findings on the role of the actin cytoskeleton in apical and basal PIN targeting, and identify a previously unknown role for microtubules, specifically in basal targeting. PIN protein delivery to different sides of the cell is mediated by ARF-dependent trafficking with a previously unknown complex level of distinct ARF-GEF vesicle trafficking regulators. Our data suggest that alternative recruitment of PIN proteins by these distinct pathways can account for cell type- and cargo-specific aspects of polar targeting, as well as for polarity changes in response to different signals. The resulting dynamic PIN positioning to different sides of cells defines a three-dimensional pattern of auxin fluxes within plant tissues.
Molecular and cellular aspects of auxin-transport-mediated development
Publisher: Elsevier BV
Date: 04-2007
DOI: 10.1016/J.TPLANTS.2007.03.006
Abstract: The plant hormone auxin is frequently observed to be asymmetrically distributed across adjacent cells during crucial stages of growth and development. These auxin gradients depend on polar transport and regulate a wide variety of processes, including embryogenesis, organogenesis, vascular tissue differentiation, root meristem maintenance and tropic growth. Auxin can mediate such a perplexing array of developmental processes by acting as a general trigger for the change in developmental program in cells where it accumulates and by providing vectorial information to the tissues by its polar intercellular flow. In recent years, a wealth of molecular data on the mechanism of auxin transport and its regulation has been generated, providing significant insights into the action of this versatile coordinative signal.
ARF GEF-Dependent Transcytosis and Polar Delivery of PIN Auxin Carriers in Arabidopsis
Publisher: Elsevier BV
Date: 04-2008
DOI: 10.1016/J.CUB.2008.03.021
Abstract: Cell polarity manifested by the polar cargo delivery to different plasma-membrane domains is a fundamental feature of multicellular organisms. Pathways for polar delivery have been identified in animals prominent among them is transcytosis, which involves cargo movement between different sides of the cell [1]. PIN transporters are prominent polar cargoes in plants, whose polar subcellular localization determines the directional flow of the signaling molecule auxin [2, 3]. In this study, we address the cellular mechanisms of PIN polar targeting and dynamic polarity changes. We show that apical and basal PIN targeting pathways are interconnected but molecularly distinct by means of ARF GEF vesicle-trafficking regulators. Pharmacological or genetic interference with the Arabidopsis ARF GEF GNOM leads specifically to apicalization of basal cargoes such as PIN1. We visualize the translocation of PIN proteins between the opposite sides of polarized cells in vivo and show that this PIN transcytosis occurs by endocytic recycling and alternative recruitment of the same cargo molecules by apical and basal targeting machineries. Our data suggest that an ARF GEF-dependent transcytosis-like mechanism is operational in plants and provides a plausible mechanism to trigger changes in PIN polarity and hence auxin fluxes during embryogenesis and organogenesis.
Generalist insects behave in a jasmonate-dependent manner on their host plants, leaving induced areas quickly and staying longer on distant parts
Publisher: The Royal Society
Date: 07-04-2013
Abstract: Plants are sessile, so have evolved sensitive ways to detect attacking herbivores and sophisticated strategies to effectively defend themselves. Insect herbivory induces synthesis of the phytohormone jasmonic acid which activates downstream metabolic pathways for various chemical defences such as toxins and digestion inhibitors. Insects are also sophisticated animals, and many have coevolved physiological adaptations that negate this induced plant defence. Insect behaviour has rarely been studied in the context of induced plant defence, although behavioural adaptation to induced plant chemistry may allow insects to bypass the host's defence system. By visualizing jasmonate-responsive gene expression within whole plants, we uncovered spatial and temporal limits to the systemic spread of plant chemical defence following herbivory. By carefully tracking insect movement, we found induced changes in plant chemistry were detected by generalist Helicoverpa armigera insects which then modified their behaviour in response, moving away from induced parts and staying longer on uninduced parts of the same plant. This study reveals that there are plant-wide signals rapidly generated following herbivory that allow insects to detect the heterogeneity of plant chemical defences. Some insects use these signals to move around the plant, avoiding localized sites of induction and staying ahead of induced toxic metabolites.
Strigolactones Suppress Adventitious Rooting in Arabidopsis and Pea
Publisher: Oxford University Press (OUP)
Date: 08-02-2012
Abstract: Adventitious root formation is essential for the propagation of many commercially important plant species and involves the formation of roots from nonroot tissues such as stems or leaves. Here, we demonstrate that the plant hormone strigolactone suppresses adventitious root formation in Arabidopsis (Arabidopsis thaliana) and pea (Pisum sativum). Strigolactone-deficient and response mutants of both species have enhanced adventitious rooting. CYCLIN B1 expression, an early marker for the initiation of adventitious root primordia in Arabidopsis, is enhanced in more axillary growth2 (max2), a strigolactone response mutant, suggesting that strigolactones restrain the number of adventitious roots by inhibiting the very first formative isions of the founder cells. Strigolactones and cytokinins appear to act independently to suppress adventitious rooting, as cytokinin mutants are strigolactone responsive and strigolactone mutants are cytokinin responsive. In contrast, the interaction between the strigolactone and auxin signaling pathways in regulating adventitious rooting appears to be more complex. Strigolactone can at least partially revert the stimulatory effect of auxin on adventitious rooting, and auxin can further increase the number of adventitious roots in max mutants. We present a model depicting the interaction of strigolactones, cytokinins, and auxin in regulating adventitious root formation.
Related Organisations
University Of Bristol
Location: United Kingdom of Great Britain and Northern Ireland
Massachusetts Institute Of Technology, MIT
Location: United States of America
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