title: Exploring bacterial community structure and function associated with atrazine biodegradation in repeatedly treated soils.
abstract: Substantial application of the herbicide atrazine in agriculture leads to persistent contamination, which may damage the succeeding crops and pose potential threats to soil ecology and environmental health. Here, the degradation characteristics of atrazine and dynamic change of soil bacterial community structure and function as well as their relations were studied during three repeated treatments at the recommended, double, and five-fold doses. The results showed that the degradation half-life of atrazine obviously decreased with increased treatment frequency. Soil microbial functional diversity displayed a variation trend of suppression-recovery-stimulation, which was associated with increased degradation rate of atrazine. 16S amplicon sequencing was conducted to explore bacterial community structure and correlate the genus to potential atrazine degradation. A total of seven potentially atrazine-degrading bacterial genera were found including Nocardioides, Arthrobacter, Bradyrhizobium, Burkholderia, Methylobacterium, Mycobacterium, and Clostridium. These bacterial genera showed almost complete atrazine degradation pathways including dechlorination, dealkylation, hydroxylation, and ring cleavage. Furthermore, the relative abundance of four of them (i.e., Nocardioides, Arthrobacter, Methylobacterium, and Bradyrhizobium) increased with treatment frequency and atrazine concentration, suggesting that they may participate in atrazine degradation during repeated treatments. Our findings reveal the potential relationship between atrazine degradation and soil bacterial community structure in repeatedly treated soils.
authors.affiliation: Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Fang
authors.affiliation: Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Lian
authors.affiliation: Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China.
authors.forename: Huifang
authors.initials: H
authors.lastname: Wang
authors.affiliation: Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Cai
authors.affiliation: Institute of Pesticide and Environmental Toxicology, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China. Electronic address: ylyu@zju.edu.cn.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Yu
mesh_terms: D001280:Atrazine / Q000378:metabolism*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism; D001673:Biodegradation, Environmental; D044822:Biodiversity; D004269:DNA, Bacterial / Q000032:analysis; D006540:Herbicides / Q000378:metabolism*; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D006540:Herbicides; D001280:Atrazine
keywords: 16S rRNA gene; Atrazine; Community structure; Degradation; Functional diversity