Waterlogging disrupts soil-microbe-metabolite interactions in the pepper rhizosphere, driving wilt disease emergence

Abstract

The phenomenon of pepper wilt has increasingly emerged as a significant factor contributing to yield reduction; however, a clear understanding of its underlying causes remains elusive. Inter-root microorganisms can influence plant growth by facilitating the transport of foreign substances into the plant through various mechanisms. We aimed to explore the key microbial factors affecting pepper wilt by analyzing pepper inter-root soils. We conducted a comprehensive analysis of soils from healthy and wilt-affected pepper regions, evaluating their physicochemical properties, microbiome composition, and metabolomics. Healthy soils were found to have higher magnesium, iron, potassium, microbial carbon, and cation exchange capacity. Microbiome sequencing showed that healthy soils were dominated by PTLA13, Lysobacter, Sphingomonas, Pseudomonas, Mortierella, Bionectriaceae, Sordariales, and Onygenaceae, which were more prevalent in healthy regions, whereas A4b_norank and Agaricales fungi were more commonplace in wilted regions. Metabolomics revealed GL glycerides in wilted regions and lignans and coumarins in healthy ones. We suggest that the combined effects of changes in soil physical and chemical properties, shifts in unique microbial communities, organisms, and variations in the increase or decrease in metabolite concentrations collectively impact the health of the microecology surrounding the pepper inter-root. These interactions may trigger abnormal plant growth responses to external stressors, potentially increasing the incidence of pepper wilt in subsequent years.