Microbial Inoculant GB03 Increased the Yield and Quality of Grape Fruit Under Salt-Alkali Stress by Changing Rhizosphere Microbial Communities

Beneficial microbial agents, renowned for their cost-effectiveness, high efficiency, and environmental sustainability, play a pivotal role in enhancing plant growth, crop yield, and tolerance to abiotic stresses. This research delves into the impact of the GB03 microbial agent on the fruit quality of '<i>Cabernet Sauvignon</i>' grapes, as well as on soil physicochemical properties and microbial communities under saline stress. The findings revealed that salt-alkali stress significantly elevated soil electrical conductivity, pH, Na⁺ levels, and total salt content, while it markedly reduced soil K⁺, organic matter, ammonium nitrogen, and nitrate nitrogen levels compared to the control. The application of the GB03 microbial agent, however, successfully mitigated these detrimental effects of salt-alkali stress. Furthermore, it augmented the population and abundance of dominant soil bacteria, including <i>Acidobacteriota</i>, <i>Bdellovibrionota</i>, and <i>Gemmatimonadota</i> etc., under saline conditions. Crucially, the microbial agent also inhibited the salt-alkali stress-induced decline in grape fruit's single cluster weight, 100-grain weight, fruit color intensity, and volatile aroma compounds, as well as the increase in organic acids. Consequently, the GB03 microbial agent emerges as a potent strategy for ameliorating saline-alkali soils and bolstering the salt-alkali stress resilience of horticultural crops like grapes.