Transcriptomic analyses of wild Vitis species under drought conditions for next-generation breeding of grapevine rootstocks

Abstract

Drought is one of the main challenges for viticulture in the context of climate change. Selecting drought-tolerant plant material can be an effective strategy for a sustainable viticulture. The choice of rootstock is a relevant way of adaptation to future environmental conditions as we can improve plant performance without modifying the scion variety and thus the wine composition. For this purpose, breeding new rootstocks is essential since currently used rootstocks have a narrow genetic diversity that could compromise their ability to adapt to new environmental conditions. Thus, exploiting a wider range of wild Vitis species for the innovation of new grapevine rootstock varieties is crucial. The aim of our work was to identify the molecular determinants of root drought responses in a wide range of unexplored wild Vitis species and identify interesting genotypes for rootstock breeding. For this purpose, we characterized the response of cuttings from ten wild Vitis accessions, from three different species (V. acerifolia, V. candicans and V. doaniana) to moderate drought with a focus on root morphological and molecular responses. The plants were submitted to water stress (30% of soil water capacity) for 4 weeks in a greenhouse. RNA sequencing data were generated from roots of all ten accessions and differential gene expression analyses were conducted. The results show a high conservation of core gene expressions responses to drought; interesting genes include a range of MYB transcription factors. In addition, species-specific gene expression patterns were identified. Our results highlight high intra-specific variability in root gene expression profiles in response to drought. These outcomes contribute to decipher the genetic regulation of root drought responses in wild Vitis species.