Unraveling Mechanisms and Impact of Microbial Recruitment on Oilseed Rape ( L.) and the Rhizosphere Mediated by Plant Growth-Promoting Rhizobacteria.

Plant growth-promoting rhizobacteria (PGPR) are noticeably applied to enhance plant nutrient acquisition and improve plant growth and health. However, limited information is available on the compositional dynamics of rhizobacteria communities with PGPR inoculation. In this study, we investigated the effects of three PGPR strains, , , and on the ecophysiological properties of Oilseed rape (), rhizosphere, and bulk soil; moreover, we assessed rhizobacterial community composition using high-throughput Illumina sequencing of 16S rRNA genes. Inoculation with , , and , significantly increased the plant total N (TN) ( < 0.01) content. and selectively enhanced the growth of and , whereas could recruit diazotrophic rhizobacteria, members of and , whose abundance was positively correlated with inoculation, and improved the transformation of organic nitrogen into inorganic nitrogen through the promotion of ammonification. Initial colonization by PGPR in the rhizosphere affected the rhizobacterial community composition throughout the plant life cycle. Network analysis indicated that PGPR had species-dependent effects on niche competition in the rhizosphere. These results provide a better understanding of PGPR-plant-rhizobacteria interactions, which is necessary to develop the application of PGPR.