Pathogen-related specificity of subtilase VVISBT4.19 X1 in the Vitis vinifera defence response

Abstract

Grapevine, Vitis vinifera L., is one of the most cultivated fruit plants worldwide with high economic value. Powdery mildew and gray mold diseases, caused by Erysiphe necator and Botrytis cinerea, respectively, are within the most devastating diseases, which are controlled by using several fungicide applications over a single growing season. A more sustainable and environmentally friendly alternative for pest control is associated to the development of breeding programs, in which American and Asian Vitis species, presenting natural resistance characteristics, are crossed with V. vinifera varieties that are susceptible to diseases caused by fungal or oomycete pathogens. As a result, new grapevine varieties that combine the good berry quality with a high degree of resistance to grapevine pathogens are obtained. One example is the Vitis vinifera cv ‘Regent’ that acquired high tolerance degree against E. necator and Plasmopara viticola. To ensure durable resistance introgression in breeding programs, a full understanding of grapevine defence mechanisms is crucial. Previous studies on grapevine-P. viticola pathosystem have suggested the participation of serine proteases in the establishment of the interaction between both organisms, which is the case of VviSBT4.19 X1. The gene expression of this subtilase increases up to 300-fold 6 hours after ‘Regent’ inoculation with P. viticola. Nowadays, no information is available about the participation of subtilases in grapevine response to E. necator and B. cinerea infection. In the present study, the gene expression profile of VviSBT4.19 X1 in the first hours of ‘Regent’ inoculation with E. necator and B. cinerea was analysed to understand its response towards different pathogenic agents.