The Role of Rhizosphere Microorganisms and CNPS Genes in Shaping Nutritional Traits of Capsicum

The rhizosphere microbiota plays crucial roles in biogeochemical cycling and primary production. However, there is a lack of research exploring the complex relationships between microbiota and their functional traits in pepper rhizospheres, as well as their impact on nutrient cycling processes. Here, we investigated the effects of pepper species on the rhizomicrobiota and functional genes (C/N/P/S) on nutrient absorptions and accumulations in pepper organs. The results revealed that Pepper YZ/BE had higher N content in all compartments, which could be attributed to the presence of enriched N-metabolic microbes (Gaiellales/Leifsonia) and higher expression of N availability-promoting genes (ureC/amoA2/nxrA/napA) in rhizospheres. Additionally, we utilized co-occurrence network analysis and partial least squares path modeling (PLS-PM) to understand the interactions among the variables. The bacterial network exhibited more associations than the fungal network, and the abundance of certain modules positively correlated with the expression of CNPS genes, which thus significantly influenced pepper nutrient content. The PLS-PM analysis demonstrated that taxa abundance in network modules, functional genes, and rhizospheric soil properties collectively explained 92% of the variance in pepper nutrient content. Overall, this study provides valuable experimental and theoretical insights into the effects of rhizosphere microorganisms and CNPS genes on the nutritional traits of Capsicum. HighlightThe rizho-bacterial community harbored more robust relationships than the fungal ones, which formed the functional clusters highly linking to the below- and aboveground nutrient properties of pepper species.