Mila Mulati

and 5 more

To elucidate the diversity of glyphosate-degrading bacterium and genes in arid and alkaline soil environments. From the long-term continuously cropped saline-alkali cotton soil in Xinjiang, a highly efficient glyphosate-degrading bacterial community, designated as CW, was enriched and propagated. In MSM medium with a pH of 8.0, this community could completely degrade 500 mg/L of glyphosate within 36h. The CW community is predominantly composed of over 20 genera belonging to the phyla Proteobacteria, Firmicutes, and Bacteroidetes. Notable genera include Hyphomicrobium, Pseudoxanthomonas, and Aquamicrobium. 24 strains from 9 genera, each exhibiting high glyphosate-degrading capabilities, were isolated. Among these, 12 strains from six genera - Aquamicrobium, Shinella, Pseudomonas, Nocardioides, Chitinophaga, and Pseudomonas - achieved a 100% degradation rate. During the degradation of glyphosate by the bacterial community CW, intermediate metabolites such as AMPA and phosphate were detected. Moreover, sarcosine was detected during the degradation process by the bacterial strain W6/7. A more in-depth analysis of the glyphosate-degrading genes indicated that, apart from the thiO, GAT, and phnY gene sequences, the genomes of the bacterial strain W6/7 also contained sequences highly similar to the reported glyphosate-degrading genes soxA, aroA, dadA, phnJ, phnD, and phnA. Notably, the community CW efficiently expressed all the above mentioned genes. Additionally, during glyphosate degradation, genes involved in the metabolism of phosphonates, hypophosphonates, oxalates, and dicarboxylates were also expressed. This study reveals that, even in the unique soil environment of Xinjiang, there exists a highly diverse bacterial community capable of the complete and efficient degradation of glyphosate.