Metagenomic analysis reveals potential biodegradation pathways of persistent pesticides in freshwater and marine sediments.
The abundance and diversity of biodegradation genes (BDGs) and potential degradation pathways of dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), and atrazine (ATZ) in freshwater and marine sediments were investigated by metagenomic analysis using 6 datasets (16Gb in total). The datasets were derived using Illumina high-throughput sequencing and were based on BLAST against self-established databases of BDGs, DDT degradation genes (DDGs), HCH degradation genes (HDGs), and ATZ degradation genes (ADGs). The results showed that the abundance and diversity of BDGs, DDGs, HDGs, and ADGs varied with sample source and locations. The lip and mnp genes, which encode for peroxidase, and the carA gene, which encodes for laccase, were detected as the dominant genes for degradation of organic pollutants. The hdt, hdg, and atzB genes, which encode for hydratase, dehalogenase, and ethylaminohydrolase, were found to be the most abundant genes involved in DDT, HCH, and ATZ degradation, respectively. The identified 69 genera capable of degrading organic pollutants were mostly affiliated with Proteobacteria (49.3%) and Actinobacteria (21.7%). Four genera, including Plesiocystis, Anaerolinea, Jannaschia, and Mycobacterium, were the major biodegradation populations in all sediments. In this study, the nearly complete biodegradation pathways of DDT and ATZ were found, and the partial degradation pathway of HCH was detected in all sediments.
Environmental Biotechnology Laboratory, The University of Hong Kong, Pokfulam Road, Hong Kong; Institute of Pesticide and Environmental Toxicology, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
Hua
H
Fang
Environmental Biotechnology Laboratory, The University of Hong Kong, Pokfulam Road, Hong Kong.
Lin
L
Cai
Environmental Biotechnology Laboratory, The University of Hong Kong, Pokfulam Road, Hong Kong.
Ying
Y
Yang
Environmental Biotechnology Laboratory, The University of Hong Kong, Pokfulam Road, Hong Kong.
Feng
F
Ju
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Xiangdong
X
Li
Institute of Pesticide and Environmental Toxicology, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
Yunlong
Y
Yu
Environmental Biotechnology Laboratory, The University of Hong Kong, Pokfulam Road, Hong Kong. Electronic address: zhangt@hku.hk.
Tong
T
Zhang
D001673:Biodegradation, Environmental; D003634:DDT / Q000032:analysis; D005618:Fresh Water / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry*; D001556:Hexachlorocyclohexane / Q000032:analysis*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis; D054892:Metagenome / Q000502:physiology*; D056186:Metagenomics; D010575:Pesticides / Q000032:analysis*; D012623:Seawater / Q000737:chemistry; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis*
D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D014874:Water Pollutants, Chemical; D001556:Hexachlorocyclohexane; D003634:DDT
Biodegradation pathway; DDT; HCH; High-throughput sequencing; Pesticide; Sediment