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Parental and environmental control of seed dormancy; Control of seed germination by biotic factors

English title Parental and environmental control of seed dormancy; Control of seed germination by biotic factors
Applicant Lopez-Molina Luis
Number 179472
Funding scheme Project funding
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 01.04.2019 - 31.03.2023
Approved amount 800'000.00
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All Disciplines (2)

Discipline
Molecular Biology
Genetics

Keywords (10)

Cold; Gibberellic acid; Pseudomonas; Imprinting; DELLA; Germination; DNA methylation; Dormancy; Arabidopsis; Abscisic acid

Lay Summary (French)

Lead
Dans le cadre de ce nouveau projet nous étudierons les mécanismes épigénétiques associés au contrôle parental et environnemental de la germination dans le contexte de la dormance chez Arabidopsis thaliana. Nous étudierons également comment des facteurs biotiques émis par la bactérie Pseudomonas aeruginosa exercent leur action pour bloquer la germination des graines.
Lay summary

Le projet se divise en trois parties.

1) Nous avons identifié des gènes exprimés dans l’endosperme soumis à l’empreinte génomique et qui participent au contrôle parental de la dormance. Nous étudierons les mécanismes épigénétiques sous-jacents au contrôle parental de la dormance en identifiant les modifications de l’ADN ou des histones responsables pour l’empreinte génomique.

2) De nombreux gènes soumis à l’empreinte génomique ont leur expression régulée par le froid qui joue un rôle majeur dans les niveaux de dormance finaux emmagasinés dans la graine. Nous étudierons si le froid modifie les marques épigénétiques et si ces modifications régulent à leur tour le contrôle de la dormance.

3) Le contrôle biotique de la germination est mal connu. En collaboration avec le groupe du Prof Jean-Luc Wolfender (UNIGE), nous avons récemment identifié une molécule sécrétée par la bactérie pathogène Pseudomonas aeruginosa qui inhibe la germination chez Arabidopsis thaliana en recrutant les voies de signalisation déjà connues qui sont impliquées dans le contrôle de la germination en réponse aux facteurs abiotiques. Nous étudierons la façon dont cette molécule agit sur ces voies de signalisation.

Comprendre comment les grains contrôlent leur germination est important non seulement pour l’agriculture mais également pour comprendre la distribution des différentes espèces de plantes dans un monde exposé à un changement climatique rapide. 

Direct link to Lay Summary Last update: 24.08.2018

Responsible applicant and co-applicants

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Associated projects

Number Title Start Funding scheme
152660 Selected topics on the control of seed germination: light, temperature and dormancy 01.01.2015 Project funding

Abstract

In the course of our past FNRS grants we studied the molecular genetic mechanisms underlying the control of seed germination in plants by the phytohormones abscisic acid (ABA) and gibberellic acid (GA) in the model organism Arabidopsis thaliana. More recently we broadened our outlook by studying control of germination in dormant seeds or in response to abiotic parameters such as light quality. This grant application, divided in three subprojects, continues to explore the multiple facets of how seeds control their germination by focusing on mechanistic aspects of two poorly understood cases: regulation of seed dormancy levels and control of seed germination by biotic factors.1. We recently identified a dynamic program of imprinted gene expression in the mature seed endosperm and found that at least two imprinted genes mediate mother-of-origin inheritance of seed dormancy levels through maternal alleles in the gametophyte. We propose to identify the imprints, i.e. the DNA or histone modifications, sustaining the preferential expression of one of the parental alleles. Furthermore, the pathways regulating the depositions of these imprints and their role for the parental control of seed dormancy will be studied. In summary, the first subproject proposes the identification and developmental study of the epigenetic marks associated with the parental control of seed dormancy.2. Exposure of mother plants to cold temperatures markedly increases the dormancy levels of their seed progeny. How seeds remember past temperatures experienced by their mother plant is poorly understood. We showed that cold temperatures decrease the expression of the majority of imprinted genes in the endosperm upon imbibition, including those regulating seed dormancy. We recently found cold-dependent increase in DNA methylation levels as a potential mechanism regulating dormancy. We propose to further characterize DNA and histone modifications triggered by cold, the signaling pathways involved and their role to control seed dormancy. In summary, the second subproject proposes the identification and developmental study of the epigenetic marks associated with low temperature control of seed dormancy.3. We recently identified, in collaboration with Dr Jean-Luc Wolfender (UNIGE), an oxyvinylglycine compound released by Pseudomonas aeruginosa that is able to repress Arabidopsis seed germination. This compound is associated with P. aeruginosa quorum sensing system activity and was also previously proposed to repress germination of graminaceous seeds but its precise effect in plants is unknown. We found that repression of germination by this oxyvinylglycine requires the activation of the GA and ABA pathways. We propose a series of genetic, genomic, metabolomics and hypothesis-driven approaches to identify the molecular targets of this biotic factor in Arabidopsis. The third subproject is therefore concerned with the control of seed germination by biotic factors.
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