SHIFT IN SOIL MICROBIAL COMMUNITY OF COWPEA DUE TO ROOT ROT INFECTION

The impact of plant health status change, specifically the effect of root rot infection, on rhizosphere microbial structure remains unclear. To address this knowledge gap, we investigated the dynamic variations in soil nutrient and rhizosphere microbial community during cowpea root rot infection. Samples of healthy and moderately to severely diseased cowpea rhizosphere soil were collected from a field in Xiangyang, Hubei, China, and high-throughput sequencing was used to detect changes in soil microbial communities. Our results showed that cowpea biomass decreased significantly with increased disease severity, and differences in soil pH and nutrients (NO3--N, NH4+-N, and available phosphorus) were observed between healthy and diseased rhizosphere, particularly under moderate diseased conditions. The process of root rot infection affected the bacterial and fungal community structure in the rhizosphere, but with inconsistent responses. Specifically, bacterial richness decreased with increased disease severity, while minor differences were observed in fungal alpha diversity. Principal coordinate analysis revealed significant disparities in rhizosphere bacteria and fungi under healthy and diseased conditions (moderate and severe). Moreover, while bacterial communities underwent notable alterations, fungal communities exhibited no significant changes between moderate and severe diseased conditions. In addition, Redundancy analysis showed that bacteria beta diversity was determined by available potassium and pH in the rhizosphere, whereas fungal beta diversity was determined by soil organic matter and pH. Overall, with root rot infection, both the soil nutrients and microbial community structure of cowpea significant changed. As a result, our study provides insights into the molecular mechanism underlying cowpea root rot and other plant rhizosphere microbial communities.