Rhodopseudomonas palustris J1-supplemented microbial fertilizers improve soil microbial communities, soil enzyme activities, and root metabolism of tobacco

Microbial fertilizer could influence soil microbial communities and improve plant growth and development. This study revealed the effect of three kinds of microbial fertilizers from the perspectives of root metabolome, soil microbial communities, and soil enzymes, aiming to provide a novel fertility strategy for improving the agricultural production of tobacco. Field experiments were conducted with three kinds of microbial fertilizers, including Rhodopseudomonas palustris J1 , Bacillus amyloliquefaciens , and Bacillus subtilis . The growth and economic benefits of tobacco under different fertility strategies were estimated. The root metabolome and rhizosphere microbial communities were analyzed. Additionally, changes in the activities of soil enzymes were also assessed. Rhodopseudomonas palustris J1 showed the most significant promoted effect on the growth and economic benefits of tobacco. Among three microbial fertilizers, Rhodopseudomonas palustris J1 significantly affected the metabolome of tobacco roots, where the Pentose phosphate pathway and Glycerophospholipid metabolism were significantly enriched. The effects of Bacillus amyloliquefaciens and Bacillus subtilis were not significant. For the rhizosphere microbial communities, Rhodopseudomonas palustris J1 significantly increased the diversity, richness, and stability, and the microbial community structure also showed significant changes. Moreover, all three microbial fertilizers significantly promoted the activity of UE and SC, and the effect of Rhodopseudomonas palustris J1 was the strongest. For the activity of CAT, only Rhodopseudomonas palustris J1 exerted a significant increase. Rhodopseudomonas palustris J1 could promote tobacco growth and improve its economic benefits by improving microbial community stability and composition, promoting tobacco root metabolism and development, and enhancing soil enzyme activities. • Rhodopseudomonaspalustris J1 showed the most significantly promoted effect. • The Pentose phosphate and Glycerophospholipid metabolism were affected. • The activities of UE, SC, and CAT showed significant response. • The microbial community diversity, stability, and structure significantly changed.