Clarifying the role of DNA methylation in tree phenotypic plasticity
Résumé
In a context of global climate change, trees as sessile and long lifespan organisms need to develop mechanisms enabling
them to adapt and to survive. These last years, epigenetic mechanisms such as DNA methylation have been proposed as a
valuable resource since they can be triggered by the environmental conditions in a reversibleway. However, evidences for
their role in tree phenotypic plasticity are still lacking (Bräutigam et al., 2013; Plomion et al., 2016). In this context, we
develop different complementary approaches:
i) A correlative approach with simultaneous analysis of methylome and transcriptome dynamics in the shoot apical
meristem (center of shoot morphogenesis) of poplar in various environments (Gourcilleau et al., 2010; LafonPlacette et
al., 2013; Bastien et al., 2015; Le Gac, 2017; LafonPlacette et al., 2017).
ii) A reverse genetic approach, using RNAi clones of Populus tremula x alba (Zhu et al., 2013; Condé et al., 2017; Le
Gac et al., in prep) hypo or hypermethylated and grown under environmental constraints.
iii) A population approach, using natural populations from diverse geographic origins to explore microevolutive
adaptation to local environment and phenotypic plasticity (Project ‘EPITREE’ ANR 20182021, S. Maury). Our previous
data highlight a relationship between DNA methylation in the shoot apical meristem biomass productivity and a possible
connection with phytohormone signaling in response to abiotic stress. New data will be also presented concerning the
stability of the epigenetic modifications and their genetic diversity in populations. Altogether, our data provide new
insights into how trees modulate their epigenomes to ensure developmental plasticity and adaptation in a changing
environment.
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