Microbiome-engineered grapevines – A novel solution for healthy future vineyards

Abstract

Grapevine trunk disease (GTD) is one of the most destructive threats to vineyards, with its ongoing spread posing a major challenge to the long-term sustainability of viticulture worldwide. Mitigation is difficult due to the disease's complex etiology. It is caused by multiple fungal pathogens, has a long and variable latency period, and there are no curative treatments. While there is some variation in susceptibility among grapevine cultivars, no variety is fully resistant. Notably, Sauvignon Blanc, New Zealand’s flagship variety, is the most susceptible and accounts for 78% of the national yield. Preliminary data show that certain grapevines thriving in GTD hotspots possess distinct microbiomes. This finding suggests that the microbiome may serve as a genetic reservoir for disease resistance. We analysed metabarcoding data from over 300 vines, phenotyped for GTD symptoms across 10 vineyards, to identify microbial taxa uniquely associated with disease-free vines. The taxa identified from metabarcoding analyses and those recovered as live cultures will be screened using in vitro functional testing (e.g., secretion of antagonistic or volatile compounds, siderophore production) to understand their modes of action. Compatible microbial taxa, including spontaneous rifampicin-resistant mutants, will be grouped using pairwise analysis to form three synthetic microbial communities (SynComs), which will be infiltrated into 1-year-old canes, to study their movement and dynamics in planta. These SynCom-augmented vines will be challenged with GTD pathogens and transcriptome analysis combined with symptom analysis will be used to examine their effect on disease expression over time. This research aims to enhance grapevine resistance to GTD by introducing beneficial microbiomes during the nursery propagation stage.