Subtilisin-like proteins and lipid signalling events: the missing links in grapevine resistance to Plasmopara viticola

Abstract

The reduction of phytochemicals used to control pests and diseases is one of the demands on modern agriculture. Grapevine is one of the most important crops grown in temperate climates, where Europe's wine industry represents 40% of the world production. The cultivated grapevine, Vitis vinifera, is prone to several diseases, with downy mildew being among the most devastating. Preventive fungicide applications are used each growing season to control disease incidence, with major environmental and economic constraints. A deeper knowledge on the grapevine-Plasmopara viticola interaction is needed to define alternative disease-control strategies. We have shown that, during the first hours of interaction with P. viticola, the modulation of chloroplast-associated lipids is important for protection of the photosynthetic machinery and biosynthesis of jasmonic acid (JA). We have also identified subtilisin-like proteases as strong resistance-associated candidates. In the present study, we have assessed the link between JA elicitation and both fatty acid (FA) and immunity-related subtilase expression modulation. Our results show that FA modulation after JA elicitation is similar to that described previously after P. viticola inoculation and that immunity-related subtilase expression also increases in the tolerant genotype, particularly the subtilase VviSBT5.3a, thus suggesting a shared mechanism.