Degradation of Cyhalofop-butyl (CyB) by Pseudomonas azotoformans Strain QDZ-1 and Cloning of a Novel Gene Encoding CyB-Hydrolyzing Esterase
Degradation of Cyhalofop-butyl (CyB) by Pseudomonas azotoformans Strain QDZ-1 and Cloning of a Novel Gene Encoding CyB-Hydrolyzing Esterase
复制标题
偶氮假单胞菌菌株 QDZ-1 降解氰氟草酯 (CyB) 及编码 CyB 水解酯酶的新基因的克隆
DOI：
10.1021/jf200397t
复制
发表时间：
2011-06-08
影响因子：
6.1
通讯作者：
Li, Shun-Peng
中科院分区：
文献类型：
--
作者：
Nie, Zhi-Juan;Hang, Bao-Jian;Li, Shun-Peng
Cyhalofop-butyl (CyB) is a widely used aryloxyphenoxy propanoate (AOPP) herbicide for control of grasses in rice fields. Five CyB-degrading strains were isolated from rice field soil and identified as Agromyces sp., Stenotrophomonas sp., Aquamicrobium sp., Microbacterium sp., and Pseudomonas azotoformans; the results revealed high biodiversity of CyB-degrading bacteria in rice soil. One strain, P. azotoformans QDZ-1, degraded 84.5% of 100 mg L-1 CyB in 5 days of incubation in a flask and utilized CyB as carbon source for growth. Strain QDZ-1 could also degrade a wide range of other AOPP herbicides. An esterase gene, chbH, which hydrolyzes CyB to cyhalofop acid (CyA), was cloned from strain QDZ-1 and functionally expressed. A chbH-disrupted mutant dchbH was constructed by insertion mutation. Mutant dchbH could not degrade and utilize CyB, suggesting that chbH was the only esterase gene responsible for CyB degradation in strain QDZ-1. ChbH hydrolyzed all AOPP herbicides tested as well as permethrin. The catalytic efficiency of ChbH toward different AOPP herbicides followed the order quizalofop-P-ethyl approximate to fenoxaprop-P-ethyl > CyB approximate to fluazifop-P-butyl > diclofop-methyl approximate to haloxyfop-P-methyl; the results indicated that the chain length of the alcohol moiety strongly affected the biodegradability of the AOPP herbicides, whereas the substitutions in the aromatic ring had only a slight influence.
