Rain-shelter cultivation promotes grapevine health by altering phyllosphere microecology in rainy areas.

Grapes are a globally significant fruit crop, but their cultivation is often challenged by leaf diseases, which limit industrial productivity. Rain-shelter cultivation has emerged as a sustainable agricultural strategy to mitigate these challenges. This study examines the effects of rain-shelter cultivation, compared to open-air cultivation, on the microclimate within the grape canopy and the microbial ecology of the grape phyllosphere. The research focused on two cultivation methods: rain-shelter and open-air cultivation. Key environmental factors such as temperature, relative humidity, and light intensity within the grape canopy were measured during the growing season. The study also explored how these conditions influence the biodiversity, stability, and functional roles of phyllosphere microbiota, particularly focusing on the community assembly processes of bacteria and oomycetes, and the efficacy of culturable microorganisms in combating grape leaf diseases. The results showed that rain-shelter cultivation signifcantly reduced leaf humidity, increased canopy temperature, and decreased light intensity, regardless of weather conditions. This approach led to a significant decrease in the incidence of grape downy mildew without affecting the overall Shannon diversity index of phyllosphere microbes. At the Class level, there was a reduction in Cystobasidiomycetes, Bacteroidia, Brocadiae, and Phycisphaerae, while Oligoflexia levels are significantly increased under rain-shelter conditions. Genus-level analysis revealed significant reductions in plant pathogens such as Erysiphe, Alternaria, and Cercospora. The study found that rain-shelter cultivation shifts fungal community assembly from stochastic to deterministic processes, while bacterial networks showed increased stability. Additionally, the beneficial microorganism Pseudomonas aeruginosa exhibited a preventive effect against grape leaf diseases, enhancing grape berry quality by increasing puncture resistance and leaf internode length. These findings provide understanding of the complex relationship between grape canopy microclimate, disease management, and microbial dynamics suggesting rain-shelter cultivation as a viable strategy for sustainable grape production, it offers insights into the research and development of future biological control agents.