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Loss of the ssrA genome island led to partial debromination in the PBDE respiring Dehalococcoides mccartyi strain GY50
Author(s) -
Ding Chang,
Rogers Matthew J.,
Yang KunLin,
He Jianzhong
Publication year - 2017
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.13817
Subject(s) - dehalogenase , strain (injury) , biology , genome , dehalococcoides , gene , polybrominated diphenyl ethers , whole genome sequencing , genetics , microbiology and biotechnology , pollutant , ecology , chemistry , organic chemistry , vinyl chloride , copolymer , anatomy , polymer
Summary Polybrominated diphenyl ethers (PBDEs), chemicals commonly used as flame‐retardants in consumer products, are emerging persistent organic pollutants that are ubiquitous in the environment. In this study, we report a PBDE‐respiring isolate – Dehalococcoides mccartyi strain GY50, which debrominates the most toxic tetra‐ and penta‐BDE congeners (∼1.4 µM) to diphenyl ether within 12 days with hydrogen as the electron donor. The complete genome sequence revealed 26 reductive dehalogenase homologous genes ( rdhA s), among which three genes ( pbrA1 , pbrA2 and pbrA3 ) were highly expressed during PBDE debromination. After 10 transfers of GY50 with trichloroethene or 2,4,6‐trichlorophenol as the electron acceptor instead of PBDEs, the ssrA ‐specific genome island ( ssrA ‐GI) containing pbrA1 and pbrA2 was deleted from the genome of strain GY50, leading to two variants (strain GY52 with trichloroethene, strain GY55 with 2,4,6‐trichlorophenol) with identically impaired debromination capabilities (debromination of penta‐/tetra‐BDEs ceased at di‐BDE 15). Through analysis of Illumina paired‐end sequencing data, we identified read pairs that probably came from variants that contain ssrA ‐GI deletions, indicating their possible presence in the original strain GY50 culture. The two variant strains provide real‐time examples on rapid evolution of organohalide‐respiring organisms. As PBDE‐respiring organisms, GY50‐like strains may serve as key players in detoxifying PBDEs in contaminated environments.