• 3 years program (2020-2023)
• 25 k€ fonctionnement + salaire thèse Mathilde Petitpas
• Funding: INRAE département BAP + Région Bretagne
• Coordinators: Mélanie Jubault, Maria Manzanares-Dauleux
• Contacts:  Melanie.jubault@agrocampus-ouest.fr, maria.manzanares-dauleux@inrae.fr

Context

As part of an environmentally friendly agriculture aimed at reducing input uses, disease genetic control is a major concern for plant breeding. Plant breeding depends on the existence and exploitation of phenotypic diversity. Up to now, plant breeding has been mainly based on natural or induced genetic variability. However, sequence variations cannot explain the whole plant phenotypic variability. The use of new sources of heritable phenotypic variation would be of interest to continue improving agronomic traits in a context of input limitation, but also to promote crop adaptation to current and future environmental constraints, especially in the context of climate change. Recent work has shown that, in addition to heritable sequence variations, epigenetic modifications are involved in the response of plants to environmental stresses and can contribute to the phenotypic diversity that can be exploited in plant breeding through heritable epimutations. However, the exploitation of these natural or induced epigenetic variations requires improving our knowledge of their contribution to the phenotype and their stability, particularly under fluctuating environmental conditions, in order to predict the impact of these epigenetic modifications on the phenotype.
Results obtained in the lab have shown that heritable variations in DNA methylation contribute to quantitative clubroot resistance (Liégard et al., 2019; Liégard & Gravot, 2019 Biorxiv) and that their expression is dependent on temperature (Liégard et al., 2019) and irrigation level (Gravot et al., 2016). This work leads us to the hypothesis that, in addition to variation of genetic origin, the modification of epigenetic regulations of genomic regions would be at the origin of the variability of host plant response to clubroot under fluctuating environmental conditions.

Objectives

The objective of this project is to establish the role of epigenetics in the response of Brassicaceae to infection by P. brassicae under fluctuating water and/or thermal conditions. How do environmental variations - such as variations in temperature or soil water status - modulate the methylome and epigenetic architecture of the plant's response to clubroot? How does the response to abiotic stress fit into the response to biotic stress? Are the factors conserved or specific between the two types of stress when they interact? Do these factors present a different epigenetic regulation according to the abiotic stress applied?