Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China.
Environ Pollut. 2023 Nov 1;336:122460. doi: 10.1016/j.envpol.2023.122460. Epub 2023 Aug 25.
Fomesafen is a diphenyl ether herbicide used to control the growth of broadleaf weeds in bean fields. The persistence, phytotoxicity, and negative impact on crop rotation associated with this herbicide have led to an increasing concern about the buildup of fomesafen residues in agricultural soils. The exigent matter of treatment and remediation of soils contaminated with fomesafen has surfaced. Nevertheless, the degradation pathway of fomesafen in soil remains nebulous. In this study, Bacillus sp. Za was utilized to degrade fomesafen residues in black and yellow brown soils. Fomesafen's degradation rate by strain Za in black soil reached 74.4%, and in yellow brown soil was 69.2% within 30 days. Twelve intermediate metabolites of fomesafen were identified in different soils, with nine metabolites present in black soil and eight found in yellow brown soil. Subsequently, the degradation pathway of fomesafen within these two soils was inferred. The dynamic change process of soil bacterial community structure in the degradation of fomesafen by strain Za was analyzed. The results showed that strain Za potentially facilitate the restoration of bacterial community diversity and richness in soil samples treated with fomesafen, and there were significant differences in species composition at phylum and genus levels between these two soils. However, both soils shared a dominant phylum and genus, Actinobacteriota, Proteoobacteria, Firmicutes and Chloroflexi dominated in two soils, with a high relative abundance of Sphingomonas and Bacillus. Moreover, an intermediate metabolite acetaminophen degrading bacterium, designated as Pseudomonas sp. YXA-1, was isolated from yellow brown soil. When strain YXA-1 was employed in tandem with strain Za to remediate fomesafen contaminated soil, the degradation rate of fomesafen markedly increased. Overall, this study furnishes crucial insights into the degradation pathway of fomesafen in soil, and presents bacterial strain resources potentially beneficial for soil remediation in circumstances of fomesafen contamination.
氟磺胺草醚是一种用于控制豆类田阔叶杂草生长的二苯醚类除草剂。由于该除草剂的持久性、植物毒性以及对轮作的负面影响，导致人们越来越关注农业土壤中氟磺胺草醚残留的积累。处理和修复受氟磺胺草醚污染土壤的迫切问题已经出现。然而，氟磺胺草醚在土壤中的降解途径仍然不清楚。在这项研究中，利用芽孢杆菌 Za 来降解黑土和黄棕壤中的氟磺胺草醚残留。菌株 Za 在黑土中 30 天内对氟磺胺草醚的降解率达到 74.4%，在黄棕壤中为 69.2%。在不同土壤中鉴定出 12 种氟磺胺草醚的中间代谢物，其中 9 种代谢物存在于黑土中，8 种存在于黄棕壤中。随后，推断了这两种土壤中氟磺胺草醚的降解途径。分析了菌株 Za 降解氟磺胺草醚过程中土壤细菌群落结构的动态变化过程。结果表明，菌株 Za 可能有助于恢复土壤样本中细菌群落的多样性和丰富度，在这两种土壤中，门和属水平的物种组成存在显著差异。然而，两种土壤都有一个优势门和属，即放线菌门、变形菌门、厚壁菌门和绿弯菌门在两种土壤中占主导地位，其中高相对丰度的属为鞘氨醇单胞菌属和芽孢杆菌属。此外，从黄棕壤中分离到一种中间代谢物对乙酰氨基酚降解菌，命名为 Pseudomonas sp. YXA-1。当菌株 YXA-1 与菌株 Za 一起用于修复氟磺胺草醚污染土壤时，氟磺胺草醚的降解率显著提高。总的来说，本研究为土壤中氟磺胺草醚的降解途径提供了重要的见解，并为氟磺胺草醚污染土壤修复提供了潜在有益的细菌菌株资源。
