The precisely regulated keystone taxa facilitate microbial mineralization of soil organic phosphorus via niche partitioning

Rhizosphere keystone taxa critically drive microbial community stability and soil biogeochemical cycles. However, the manipulation of such taxa remains a challenge. This study simulated plant-mediated modulation of keystone taxa via simplified synthetic root exudates to track their compositional shifts. The combination of luteolin, myristic acid, and glucose enhanced rhizosphere phosphatase activity, significantly enriched Domibacillus indicus D99, and converted it into a keystone taxon. This precise regulation was driven by transcriptional upregulation of C metabolism and an unusual fatty acid assimilation pathway. Additionally, metabolites produced by D. indicus D99 (such as bergapten and lactate) were preferentially utilized by phosphate-mineralizing bacteria, Bacillus sp. C67 and Domibacillus sp. C94. These partner bacteria exhibited less substrate overlap and pronounced resource partitioning, forming an efficient synergistic relationship with D. indicus D99 that amplified rhizosphere phosphatase activity and plant growth. This study highlights opportunities to utilize the ecological roles of keystone taxa in manipulating the microbiome.