Metagenomic Analysis to Assess the Impact of Plant Growth-Promoting Rhizobacteria on Peanut (<i>Arachis hypogaea</i> L.) Crop Production and Soil Enzymes and Microbial Diversity

Abstract

Peanut production could be increased through plant growth-promoting rhizobacteria (PGPR). In this regard, the present field research aimed at elucidating the impact of PGPR on peanut yield, soil enzyme activity, microbial diversity, and structure. Three PGPR strains (<i>Bacillus velezensis</i>, RI3; <i>Bacillus velezensis</i>, SC6; <i>Pseudomonas psychrophila</i>, P10) were evaluated, along with <i>Bradyrhizobium japonicum</i> (BJ), taken as a control. PGPR increased seed yield by 8%, improving the radiation use efficiency (4-14%). PGPR modified soil enzymes (fluorescein diacetate activity by 17% and dehydrogenase activity by 28%) and microbial abundance (12%). However, PGPR did not significantly alter microbial diversity; nonetheless, it modified the relative abundance of key phyla (Actinobacteria > Proteobacteria > Firmicutes) and genera (<i>Bacillus</i> > <i>Arthrobacter</i> > <i>Pseudomonas</i>). PGPRs modified the relative abundance of genes associated with N-fixation and nitrification while increasing genes related to N-assimilation and N-availability. PGPR improved agronomic traits without altering rhizosphere diversity.