Integrative study of Vitis biodiversity for next-generation breeding of grapevine rootstocks 

Drought is one of the main challenges for viticulture in the context of global change. The choice of rootstock could be leveraged for vineyard adaptation to drought as we can improve plant performance without modifying the scion variety. However, most of the existing rootstocks, selected over a century ago, have a narrow genetic background which could compromise their adaptive potential. Thus, there is a scope for innovation in grapevine rootstock varieties by exploiting a wider range of wild Vitis species. The aim of this study was to investigate the drought adaptation potential of a wide range of previously unexplored wild Vitis species, integrating information at different biological scales: from genomics, transcriptomics and metabolomics to developmental and functional root traits. Our hypothesis is that metabolites can be considered as intermediate phenotypes in roots because they are expected to be mechanistically related to more complex root phenotypes. For these purposes, we investigated genetic differentiation between species and variability within species using SNPs obtained from Illumina paired-end whole genome sequencing (4k project)^[1]. In addition, we characterized the response of cuttings from 12 American, Asian and Eurasian wild Vitis species (50 accessions in total) to moderate drought, during 1 month in a greenhouse experiment, with a focus on root morphological, functional and molecular responses (transcriptomics and metabolomics). We identified variability among species in root osmotic adjustment, an important mechanism of drought tolerance^[2]. The link between root osmotic potential and metabolites differentially accumulated in response to drought was analyzed. The results obtained in this work will help to identify new genetic resources to be used in rootstocks breeding programs to improve drought adaptation. In addition, we will provide tools to accelerate the screening of desirable traits in rootstocks using intermediate molecular phenotypes as proxies of complex root responses.

Acknowledgements:

We received funding from INRAE, University of Bordeaux (project PurVitis), Nouvelle-Aquitaine region (project VitiScope) and CNIV. We acknowledge Maria Lafargue, Cyril Hevin, Nicolas Hocquard and Jean-Pierre Petit for their help with the plant material preparation.

1)  Dong, Y.,et al. (2023). Dual domestications and origin of traits in grapevine evolution. Science, 379(6635), 892‑901.
2)  Blum, A. (2017). Osmotic adjustment is a prime drought stress adaptive engine in support of plant production. Plant, Cell & Environment, 40(1), 4‑10.