Evidence of trans-annual epigenetic memories of stresses in grapevine

Abstract

Epigenetics refers to the layer of genetic information carried in chromatin beyond the DNAsequence, including histone modifications, DNAmethylation and small RNAs. Studies in Arabidopsis, tomato and other plants have shown the influence of epigenetic mechanisms on development, agronomic traits, genome stability, and plant responses to stresses, including their memory. However, most studies have focused on annual plants, while epigenetic research in perennials remains limited. As a woody perennial, clonally propagated and commonly grafted, grapevine offers unique features that make it an attractive model for epigenetic investigations.

Here, we examine the complex response of grapevine to both biotic and abiotic stresses. We demonstrate that Esca-symptomatic plants, that display sectors with leaf symptoms alongside sectors without symptoms, present change in leaf metabolite content and gene expression profiles strictly associated with symptom development. In contrast, DNA methylation patterns are altered in leaves from both symptomatic and asymptomatic sectors compared to plants showing no disease symptoms. Some DNAmethylation changes conserved between sectors of symptomatic plants are also detected in young leaves before any visible symptom, suggesting a trans-annual memory of esca in grapevine.

We also investigate the long term consequences of drought and heat stress on clones derived from a single mother plants. Clones were grown during 4 years in contrasted environnements, and were hen trasnfered in the same growing conditions. Results indicate that the clone methylomes are clearly different after 4 years in contrasting growing conditions. In addition, some of these differences are maintained when plants are subsequently grown in the same conditions.

These data support the idea that perennials maintain a trans-annual epigenetic memory of their environment, a process likely essential for their long term adaptation to environmental challenges.

Acknowlegements

This work was supported by the program ‘Plan National Dépérissement du Vignoble’ (FranceAgriMer/CNIV) in the framework of the projects EPIDEP (Sirepa 52536) awarded to P.G. and PHYSIOPATH (22001150) awarded to C.E.L.D. M.B was in receipt of a grant financed by the program “Grand Projet de Recherche Bordeaux Plant Science” (TEPIMEMORY). B.R was in receipt of a grant financed by the program “PRIMA” (PROSIT). W.H is in receipt of a PhD grant in the frame of the project CLONADAPT awarded to PG by Plant2Pro (Institut Carnot).