Deciphering Chitosan–Host Plant Interaction in Esca Disease

Abstract

The production of wine and table grapes is hampered by Phaeomoniella chlamydospora, a fungus related to Petri diseases and Esca, two of the major grapevine trunk diseases causing the death of vines all over the world. This study analyses the effect of a commercial-based substance (chitosan hydrochloride 2.5%) on grapevine–P. chlamydospore interaction. Two experimental scenarios were evaluated: (i) root application in a greenhouse-plant model system and (ii) foliar application in an open-field environment (Tempranillo grape cultivar). Vascular necrosis and pathogen recovery were reduced after chitosan application. The treatment increased root development and the flavonoid index. On open-field application, the treatment did not significantly help decrease the expression of the foliar symptoms of Esca. In symptomatic leaves, the results revealed a lower overexpression of defence-related genes (Chit 1b, CHV5, STS and PR6) in plants treated with chitosan than in nontreated vines. Altogether, this study attempts to provide a first insight into the potential role of chitosan hydrochloride in the treatment of P. chlamydospora and the interaction on the control of the Esca–pathosystem complex. Differences were found between the root and foliar spraying modes of action.