The microbiome structure of grapevines escaping trunk diseases

Abstract

Grapevine trunk diseases (GTD), caused by a complex of fungi, continue to be one of the most devastating grapevine diseases worldwide. Grapevine trunk diseases cause yield loss and reduce the longevity of vineyards. There is no approved fungicide for eradicating GTD, and this has influenced research efforts geared towards identifying sustainable control methods for GTD management. Therefore, the primary goal of this study was to determine the microbial contribution to grapevine health. In some New Zealand vineyards, there have been anecdotal reports of grapevines that remain healthy within a background of trunk disease. This research aimed to investigate the occurrence of such grapevines – referred to here as disease escape grapevines – in the context of GTD and to explore their microbiome. Vineyards in Hawke’s Bay and Canterbury were surveyed for the presence of grapevines escaping GTD. Grapevine trunk samples were taken from putative disease escape grapevines and the symptomatic grapevines in their vicinity. The total fungal and bacterial communities of the grapevine trunk were identified by culturing and DNA metabarcoding. The DNA metabarcoding data revealed microbial taxa that were differentially abundant in disease escape grapevines and correlated negatively with GTD pathogens. Future work will involve manipulating young grapevines’ microbiome with a consortium designed from taxa of interest, followed by monitoring their proliferation, persistence and ability to suppress GTDs in planta.