Efficient degradation of phenoxyalkanoic acid herbicides by the alkali-tolerant Cupriavidus oxalaticus strain X32
Efficient degradation of phenoxyalkanoic acid herbicides by the alkali-tolerant Cupriavidus oxalaticus strain X32
复制标题
耐碱草酸铜菌株 X32 高效降解苯氧基链烷酸除草剂
DOI：
10.1021/acs.jafc.9b05061
复制
发表时间：
2020
影响因子：
6.1
通讯作者：
宗伏霖
中科院分区：
文献类型：
--
作者：
项盛;林荣华;商洪溢;徐勇;张振华;吴学民;宗伏霖
苯氧基烷酸类除草剂主要由土壤中的微生物代谢，但在碱性环境下表现良好的降解剂很少被考虑。在此，我们报告了嗜铜菌X32菌株，它表现出令人鼓舞的PAA降解能力，PAA耐受性，和碱耐受性。在液体培养基中，在不添加外源碳源的情况下，X32可以在3 d内完全去除500 mg/L的2，4-二氯苯氧乙酸（2，4-D）和4-氯苯氧乙酸（4-chloro-2-methylphenoxyacetate，4-D），比模式降解菌Cupriavidus necator JMP 134的去除速度更快。特别地，X32在pH 10.5下仍然起作用。值得注意的是，用X32接种，我们观察到2，4-D在土壤中的降解和对玉米（Zea mays）的植物毒性降低。此外，潜在的PAA生物降解和耐碱性的机制进行了分析，然后通过全基因组测序。初步鉴定了3个与2，4-D催化有关的tfd基因簇模块和编码与耐碱性有关的单价阳离子/质子反向转运蛋白的基因。因此，X32可能是一个有前途的候选人PAA污染的网站，特别是在碱性环境中的生物修复。
Phenoxyalkanoic acid (PAA) herbicides are mainly metabolized by microorganisms in soils, but the degraders that perform well under alkaline environments are rarely considered. Herein, we report Cupriavidus oxalaticus strain X32, which showed encouraging PAA-degradation abilities, PAA tolerance, and alkali tolerance. In liquid media, without the addition of exogenous carbon sources, X32 could completely remove 500 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) or 4-chloro-2-methylphenoxyacetic acid within 3 days, faster than that with the model degrader Cupriavidus necator JMP134. Particularly, X32 still functioned at pH 10.5. Of note, with X32 inoculation, we observed 2,4-D degradation in soils and diminished phytotoxicity to maize (Zea mays). Furthermore, potential mechanisms underlying PAA biodegradation and alkali tolerance were then analyzed by whole-genome sequencing. Three modules of tfd gene clusters involved in 2,4-D catabolism and genes encoding monovalent cation/proton antiporters involved in alkali tolerance were putatively identified. Thus, X32 could be a promising candidate for the bioremediation of PAA-contaminated sites, especially in alkaline surroundings.