Effect of Florpyrauxifen-Benzyl on Methane-Metabolizing Microbial Community in Rice Rhizosphere Soil

Florpyrauxifen-benzyl is a newly developed aryl pyridine carboxylic acid ester herbicide for rice paddies, and its effects on microbial communities remain largely unexplored. Rice paddy fields represent the largest source of anthropogenic methane emissions. However, whether the overapplication of florpyrauxifen-benzyl causes changes in methane-metabolizing microorganisms and consequently elevates methane emissions has not been thoroughly investigated. In this study, we investigated the effects of applying florpyrauxifen-benzyl at increasing concentrations on methane-metabolizing microorganisms, using high-throughput sequencing of functional genes involved in methane metabolism. The results were validated via quantitative fluorescence PCR. The application of florpyrauxifen-benzyl at five times the recommended dose significantly increased methane emissions. Co-occurrence network analysis revealed a more complex network structure in the methanogenic community. Furthermore, random forest modeling and LEfSe analysis indicated that Methylocystis, Methylosinus, Methanolobus, Methanosphaera, and Methanococcoides play key roles in maintaining the stability of methane-metabolizing microbial communities.