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An abscisic acid-induced developmental checkpoint in plant germination: Study of its genetic and molecular control

English title An abscisic acid-induced developmental checkpoint in plant germination: Study of its genetic and molecular control
Applicant Lopez-Molina Luis
Number 102890
Funding scheme SNSF Professorships
Research institution Département de Biologie Végétale Faculté des Sciences Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Molecular Biology
Start/End 01.09.2004 - 31.08.2008
Approved amount 1'286'459.00
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All Disciplines (5)

Molecular Biology
Embryology, Developmental Biology
Cellular Biology, Cytology

Keywords (9)

genetics; Arabidopsis; abscisic acid; gibberellic acid; AB15; PKL; chromatin; germination; plant science

Lay Summary (English)

Lay summary
Plants have evolved protective mechanisms to ensure their survival whenthreatened by adverse environmental conditions, and one of the mostfragile phases during the life cycle of flowering plants is that of seedgermination. Very early in germination and after imbibition, there is a2-3 d. period when the seeds challenged by water deficit or other forms ofstress can exercise growth arrest, which appears to be mediated by theaction of abscisic acid (ABA) and is also observed after exogenousexposure to ABA.This arrest involves, at least partially, the recruitment de novo of lateembryogenesis gene products perhaps explaining why arrested embryos aremore tolerant to osmotic stress. Thus, it seems that during germinationthere is a co-existence of two antagonistic signalling pathways: the oneof gibberellic acid (GA), promoting germination and vegetative growth, andthe one of ABA, promoting growth arrest and maintenance of embryogenesisgene products. Understanding their interaction is important from abiological developmental point of view but also for obvious agriculturalapplications.Central to the execution of this growth is the basic leucine-zippertranscription factor ABI5. Osmotic stress and ABA induce ABI5 expressionduring the 2-3d period mentioned above leading to ABI5 accumulation andgrowth arrest. However, ABA is also required for ABI5’s activity as agrowth repressor and the mechanisms of this ABA-dependent activation areunknown. The first part of this proposal is geared towards understandingthe nature of these mechanisms. We will propose a combination of molecularand genetic studies. Molecular studies will notably address the role ofphosphorylation events in ABI5 activity. Genetic studies will identifynovel gene products controlling ABI5 activity as well as test putativecandidates.In the second part of the project proposal, we will undertake a systematicstudy of the regulation of gene expression during the nine first days ofgermination i.e. upon the onset of imbibition. We will focus on a set ofkey genes, which are active and conditionally regulated by ABA and GAduring this period. The activity of these genes determine to a significantextent the “quality” of the seed germination that is: its immediateadaptation to environmental fluctuations. As part of these studies, wewill examine in some detail the role of PKL, a CHD3 domainchromatin-remodelling factor, and similar factors. Indeed, Arabidopsisoffers us with a rare opportunity to study the role of chromatinregulation in developmental transitions. The techniques used will includesodium bisulfite sequencing, chromosomal immunoprecipitations,methylation-sensitive restriction enzymes etc.
Direct link to Lay Summary Last update: 21.02.2013

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Associated projects

Number Title Start Funding scheme
120866 An abscisic acid-induced developmental checkpoint in plant germination: Study of its genetic and molecular control 01.09.2008 SNSF Professorships