Spatio-temporal dynamics of wound-induced defence responses in grapevine revealed by multiple approaches

Abstract

Grapevines are continually wounded throughout their cultivation, particularly during winter pruning. To prevent pathogen attack and tissue dehydration, plants have evolved a wide range of wound responses to protect their tissues. These responses include changes in gene expression and the synthesis of protective molecules such as polyphenols. In addition to these molecular responses, plants are known to occlude damaged xylem vessels in response to wounding and pathogen infection. Different types of occlusions can be produced, including gels, gums, and tyloses.

In this study, we explored grapevine responses to winter pruning in two different varieties. First, we studied the dynamics of xylem vessel occlusion formation at different dates during the winter months and at different depths from the wound.

Second, we characterised the gene expression changes triggered by pruning and the polyphenols that accumulated in response. Finally, we used Raman microscopy to analyse the composition of xylem vessel occlusions.

We found that the two grapevine varieties studied showed very comparable responses to winter pruning. The genes upregulated in response to pruning were highly similar between varieties and highlighted the coordinated expression of genes involved in polyphenol biosynthesis, transport processes, cutin, suberin, and wax production, as well as cell wall modifications. We also observed coordinated upregulation of stilbene synthase genes together with the accumulation of stilbenes. Raman microscopy showed that winter xylem vessel occlusions in both genotypes were gel- or gum-type structures rich in polyphenols. To our knowledge, this is the first study to combine multiple approaches to investigate grapevine responses to winter pruning.

Acknowledgements

This work was funded by the projects EFA 324/19 – VITES QUALITAS and EFA033/01 – VITRES, 65 % co-funded by the European Regional Development Fund (FEDER) through the Interreg Program V-A Spain-France-Andorra (POCTEFA 2014- 2020 and POCTEFA 2021–2027, respectively). We thank the Unité Expérimentale Vigne & Vin Bordeaux Grande Ferrade for the use of the vineyard and the Bordeaux Imaging Center for access to microscopes.