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Gerhard Leubner-metzger - One of the best experts on this subject based on the ideXlab platform.
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Beyond gibberellins and abscisic acid: how ethylene and jasmonates control Seed Germination
Plant Cell Reports, 2012Co-Authors: Ada Linkies, Gerhard Leubner-metzgerAbstract:Appropriate responses of Seeds and fruits to environmental factors are key traits that control the establishment of a species in a particular ecosystem. Adaptation of Germination to abiotic stresses and changing environmental conditions is decisive for fitness and survival of a species. Two opposing forces provide the basic physiological mechanism for the control of Seed Germination: the increasing growth potential of the embryo and the restraint weakening of the various covering layers (Seed envelopes), including the endosperm which is present to a various extent in the mature Seeds of most angiosperms. Gibberellins (GA), abscisic acid (ABA) and ethylene signaling and metabolism mediate environmental cues and in turn influence developmental processes like Seed Germination. Cross-species work has demonstrated that GA, ABA and ethylene interact during the regulation of endosperm weakening, which is at least partly based on evolutionarily conserved mechanisms. We summarize the recent progress made in unraveling how ethylene promotes Germination and acts as an antagonist of ABA. Far less is known about jasmonates in Seeds for which we summarize the current knowledge about their role in Seeds. While it seems very clear that jasmonates inhibit Germination, the results obtained so far are partly contradictory and depend on future research to reach final conclusions on the mode of jasmonate action during Seed Germination. Understanding the mechanisms underlying the control of Seed Germination and its hormonal regulation is not only of academic interest, but is also the ultimate basis for further improving crop establishment and yield, and is therefore of common importance.
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Brassinosteroids Promote Seed Germination
Brassinosteroids, 2003Co-Authors: Gerhard Leubner-metzgerAbstract:Seed Germination of Arabidopsis thaliana, Nicotiana tabacum, and of parasitic angiosperms (Orobranche and Striga species) is determined by the balance of forces between the growth potential of the embryo and the mechanical restraint of the micropylar testa and/or endosperm tissues. Brassinosteroids (BR) and gibberellins (GA) promote Seed Germination of these species and counteract the Germination-inhibition by abscisic acid (ABA). Severe mutations in GA biosynthetic genes in Arabidopsis, such as ga1-3, result in a requirement for GA application to germinate, but Germination in this phenotype can also be rescued by BR. Germination of both the BR biosynthetic mutant det2–1 and the BR-insensitive mutant bri1-1 is more strongly inhibited by ABA than is Germination of wild type. In contrast to GA, BR does not release tobacco photodormancy; i.e. Seed Germination in darkness remains blocked. BR promotes Germination of nonphotodormant tobacco Seeds, but did not appreciably affect the induction of class I ß-1,3-glucanase (ßGlu I) in the micropylar endosperm. BR and GA promote tobacco Seed Germination by distinct signal transduction pathways and distinct mechanisms. Xyloglucan endo-transglycosylase (XET) enzyme activity accumulates in the embryo and the endosperm of germinating tobacco Seeds and this appears to be partially controlled of BR. GA and light seem to act in a common pathway to release photodormancy, whereas BR does not release photodormancy. Induction of ßGlu I in the micropylar endosperm and promotion of release of ‘coat-imposed’ dormancy seem to be associated with the GA-dependent pathway, but not with BR signaling. It is proposed that BR promote Seed Germination by directly enhancing the growth potential of the emerging embryo in a GA-independent manner.
Shinjiro Yamaguchi - One of the best experts on this subject based on the ideXlab platform.
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gibberellin biosynthesis and response during arabidopsis Seed Germination
The Plant Cell, 2003Co-Authors: Mikihiro Ogawa, Atsushi Hanada, Yukika Yamauchi, Ayuko Kuwahara, Yuji Kamiya, Shinjiro YamaguchiAbstract:The hormone-mediated control of plant growth and development involves both synthesis and response. Previous studies have shown that gibberellin (GA) plays an essential role in Arabidopsis Seed Germination. To learn how GA stimulates Seed Germination, we performed comprehensive analyses of GA biosynthesis and response using gas chromatography–mass spectrometry and oligonucleotide-based DNA microarray analysis. In addition, spatial correlations between GA biosynthesis and response were assessed by in situ hybridization. We identified a number of transcripts, the abundance of which is modulated upon exposure to exogenous GA. A subset of these GA-regulated genes was expressed in accordance with an increase in endogenous active GA levels, which occurs just before radicle emergence. The GA-responsive genes identified include those responsible for synthesis, transport, and signaling of other hormones, suggesting the presence of uncharacterized crosstalk between GA and other hormones. In situ hybridization analysis demonstrated that the expression of GA-responsive genes is not restricted to the predicted site of GA biosynthesis, suggesting that GA itself, or GA signals, is transmitted across different cell types during Arabidopsis Seed Germination.
Oscar Lorenzo - One of the best experts on this subject based on the ideXlab platform.
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s nitrosylation triggers abi5 degradation to promote Seed Germination and Seedling growth
Nature Communications, 2015Co-Authors: Pablo Albertos, Maria C Romeropuertas, Kiyoshi Tatematsu, Isabel Mateos, Inmaculada Sanchezvicente, Eiji Nambara, Oscar LorenzoAbstract:Plant survival depends on Seed Germination and progression through post-germinative developmental checkpoints. These processes are controlled by the stress phytohormone abscisic acid (ABA). ABA regulates the basic leucine zipper transcriptional factor ABI5, a central hub of growth repression, while the reactive nitrogen molecule nitric oxide (NO) counteracts ABA during Seed Germination. However, the molecular mechanisms by which Seeds sense more favourable conditions and start germinating have remained elusive. Here we show that ABI5 promotes growth via NO, and that ABI5 accumulation is altered in genetic backgrounds with impaired NO homeostasis. S-nitrosylation of ABI5 at cysteine-153 facilitates its degradation through CULLIN4-based and KEEP ON GOING E3 ligases, and promotes Seed Germination. Conversely, mutation of ABI5 at cysteine-153 deregulates protein stability and inhibition of Seed Germination by NO depletion. These findings suggest an inverse molecular link between NO and ABA hormone signalling through distinct posttranslational modifications of ABI5 during early Seedling development.
Joel Vandekerckhove - One of the best experts on this subject based on the ideXlab platform.
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proteomic analysis of arabidopsis Seed Germination and priming
Plant Physiology, 2001Co-Authors: Karine Gallardo, S P C Groot, Magda Puype, Hans Demol, Joel VandekerckhoveAbstract:To better understand Seed Germination, a complex developmental process, we developed a proteome analysis of the model plant Arabidopsis for which complete genome sequence is now available. Among about 1,300 total Seed proteins resolved in two-dimensional gels, changes in the abundance (up- and down-regulation) of 74 proteins were observed during Germination sensu stricto (i.e. prior to radicle emergence) and the radicle protrusion step. This approach was also used to analyze protein changes occurring during industrial Seed pretreatments such as priming that accelerate Seed Germination and improve Seedling uniformity. Several proteins were identified by matrix-assisted laser-desorption ionization time of flight mass spectrometry. Some of them had previously been shown to play a role during Germination and/or priming in several plant species, a finding that underlines the usefulness of using Arabidopsis as a model system for molecular analysis of Seed quality. Furthermore, the present study, carried out at the protein level, validates previous results obtained at the level of gene expression (e.g. from quantitation of differentially expressed mRNAs or analyses of promoter/reporter constructs). Finally, this approach revealed new proteins associated with the different phases of Seed Germination and priming. Some of them are involved either in the imbibition process of the Seeds (such as an actin isoform or a WD-40 repeat protein) or in the Seed dehydration process (e.g. cytosolic glyceraldehyde-3-phosphate dehydrogenase). These facts highlight the power of proteomics to unravel specific features of complex developmental processes such as Germination and to detect protein markers that can be used to characterize Seed vigor of commercial Seed lots and to develop and monitor priming treatments.
Karine Gallardo - One of the best experts on this subject based on the ideXlab platform.
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Seed Germination and Vigor
Annual Review of Plant Biology, 2012Co-Authors: Loïc Rajjou, Manuel Duval, Julie Catusse, Julia Bally, Claudette Job, Karine Gallardo, Dominic JobAbstract:Germination vigor is driven by the ability of the plant embryo, embedded within the Seed, to resume its metabolic activity in a coordinated and sequential manner. Studies using "-omics" approaches support the finding that a main contributor of Seed Germination success is the quality of the messenger RNAs stored during embryo maturation on the mother plant. In addition, proteostasis and DNA integrity play a major role in the Germination phenotype. Because of its pivotal role in cell metabolism and its close relationships with hormone signaling pathways regulating Seed Germination, the sulfur amino acid metabolism pathway represents a key biochemical determinant of the commitment of the Seed to initiate its development toward Germination. This review highlights that Germination vigor depends on multiple biochemical and molecular variables. Their characterization is expected to deliver new markers of Seed quality that can be used in breeding programs and/or in biotechnological approaches to improve crop yields.
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proteomic analysis of arabidopsis Seed Germination and priming
Plant Physiology, 2001Co-Authors: Karine Gallardo, S P C Groot, Magda Puype, Hans Demol, Joel VandekerckhoveAbstract:To better understand Seed Germination, a complex developmental process, we developed a proteome analysis of the model plant Arabidopsis for which complete genome sequence is now available. Among about 1,300 total Seed proteins resolved in two-dimensional gels, changes in the abundance (up- and down-regulation) of 74 proteins were observed during Germination sensu stricto (i.e. prior to radicle emergence) and the radicle protrusion step. This approach was also used to analyze protein changes occurring during industrial Seed pretreatments such as priming that accelerate Seed Germination and improve Seedling uniformity. Several proteins were identified by matrix-assisted laser-desorption ionization time of flight mass spectrometry. Some of them had previously been shown to play a role during Germination and/or priming in several plant species, a finding that underlines the usefulness of using Arabidopsis as a model system for molecular analysis of Seed quality. Furthermore, the present study, carried out at the protein level, validates previous results obtained at the level of gene expression (e.g. from quantitation of differentially expressed mRNAs or analyses of promoter/reporter constructs). Finally, this approach revealed new proteins associated with the different phases of Seed Germination and priming. Some of them are involved either in the imbibition process of the Seeds (such as an actin isoform or a WD-40 repeat protein) or in the Seed dehydration process (e.g. cytosolic glyceraldehyde-3-phosphate dehydrogenase). These facts highlight the power of proteomics to unravel specific features of complex developmental processes such as Germination and to detect protein markers that can be used to characterize Seed vigor of commercial Seed lots and to develop and monitor priming treatments.
