Grass–Livestock–Fruit System Enhances Grape Health and Productivity by Regulating Leaf and Fruit Microbiota

The crop-livestock system is a sustainable agricultural model. Plant microbiomes play essential roles in host fitness and functionality. Here, the responses and functional roles of microorganisms in leaves and fruits were systematically investigated. Endophytic communities remained stable and predominantly beneficial, while epiphytic microorganisms responded more strongly to grass planting and sheep grazing. Grass planting increased the alpha diversity of epiphytic bacteria on leaves, while grazing enhanced the alpha diversity of epiphytic fungi, though both treatments reduced epiphytic bacterial richness on fruits. Grazing enriched potentially beneficial taxa, suppressed potential pathogens, and enhanced the bacterial metabolic potential and symbiotic fungal guilds. Correlations between microbial community variation and grape growth, health, and yield were stronger in leaves than in fruits, more pronounced for epiphytic than endophytic, and greater for bacteria than for fungi. Management simplified fruit and endophytic networks while increasing leaf epiphytic complexity. These findings reveal that microbiome-mediated mechanisms underpin the ecological benefits of integrated management.