Colletotrichum spp. and Botrytis cinerea are the main causal agents of grape bunch rot in Brazil. Although chemical control is widely used, it has limitations, such as the selection of resistant pathogen populations and environmental concerns. Biological control emerges as a promising alternative; however, commercial products for viticulture remain limited. We hypothesized that by prospecting endophytic microorganisms from berries of Vitis hosts more resistant to rots, it would be possible to identify isolates with greater biocontrol potential. In this study, 52 endophytic isolates from berries of V. labrusca cv. 'Bordô' were evaluated. In vitro assays showed mycelial growth inhibition of C. nymphaeae and B. cinerea of up to 33% and 60%, respectively. Three isolates antagonistic to both pathogens were molecularly identified as AvCaPR20-VA4L (Clavispora asparagi), AvZmPR20-VB5B (Zygoascus meyerae), and AvTmPR20-PA1N (Tatumella sp.). In postharvest assays, the isolates achieved 31.5-73.5% control of grape ripe rot (C. nymphaeae) and 39.1-59.4% control of gray mold (B. cinerea), with AvTmPR20-PA1N showing the highest efficacy, comparable to chlorothalonil. In untreated berries, disease incidence reached 53.1% for grape ripe rot and 100% for gray mold. Next-generation sequencing of the natural berry microbiota revealed the recurrent presence of Clavispora and Tatumella in non-inoculated 'Bordô' vines, confirming their natural association with grape berry tissues. These findings highlight the potential of exploring microbial diversity from naturally resistant plants as a sustainable strategy for biological disease management in viticulture.
Zela et al. (Wed,) studied this question.