Dissecting positive or negative effects of abiotic stress on grapevine self-protectioninduced by Trichoderma harzianum T39

Abstract: Downy mildew is one of the most destructive grapevine diseases, and its control isbased on the application of fungicides. There is increasing interest to reduce reliance onpesticides for disease control in viticulture and to focus on alternative methods, such asbiocontrol agents. Several Trichoderma spp. strains are active against numerous plant pathogens,and their biocontrol activity is based on different mechanisms. In grapevine, T. harzianum T39activates a plant-mediated resistance and reduces downy mildew symptoms, but its efficacyunder abiotic stress conditions have not jet investigated. Our aim is to investigate the relationshipbetween drought stress and P. viticola infection, and to characterize the efficacy of T. harzianumT39-induced resistance under water stress conditions.