TY - JOUR

T1 - Intra- and inter-field diversity of 2,4-dichlorophenoxyacetic acid-degradative plasmids and their tfd catabolic genes in rice fields of the Mekong delta in Vietnam

AU - Nguyen, Thi Phi Oanh

AU - Hansen, Martin Asser

AU - Hansen, Lars Hestbjerg

AU - Horemans, Benjamin

AU - Sørensen, Søren Johannes

AU - De Mot, René

AU - Springael, Dirk

PY - 2019

Y1 - 2019

N2 - The tfd genes mediating degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) differ in composition and organization in bacterial isolates from different geographical origin and are carried by different types of mobile genetic elements (MGE). It is not known whether such global diversity of 2,4-D-catabolic MGE and their tfd gene cargo is reflected in the diversity at field scale. The genomic context of the 2,4-D catabolic genes of 2,4-D-degrading isolates from two rice fields with a 2,4-D application history, located in two distant provinces of the Vietnam Mekong delta, was compared. All isolates were β-proteobacteria, were unique for each rice field and carried the catabolic genes on MGE and especially plasmids. Most plasmids were IncP-1β plasmids and carried tfd clusters highly similar to those of the IncP-1β plasmid pJP4, typified by two chlorophenol catabolic gene modules (tfd-I and tfd-II). IncP-1β plasmids from the same field showed small deletions and/or insertions in accessory metabolic genes. One plasmid belonged to an unclassified plasmid group and carries a copy of both tfdA and tfd-II identical to those in the IncP-1β plasmids. Our results indicate intra-field evolution and inter-field exchange of 2,4-D-catabolic IncP-1β plasmids as well as the exchange of tfd genes between different plasmids within a confined local environment.

AB - The tfd genes mediating degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) differ in composition and organization in bacterial isolates from different geographical origin and are carried by different types of mobile genetic elements (MGE). It is not known whether such global diversity of 2,4-D-catabolic MGE and their tfd gene cargo is reflected in the diversity at field scale. The genomic context of the 2,4-D catabolic genes of 2,4-D-degrading isolates from two rice fields with a 2,4-D application history, located in two distant provinces of the Vietnam Mekong delta, was compared. All isolates were β-proteobacteria, were unique for each rice field and carried the catabolic genes on MGE and especially plasmids. Most plasmids were IncP-1β plasmids and carried tfd clusters highly similar to those of the IncP-1β plasmid pJP4, typified by two chlorophenol catabolic gene modules (tfd-I and tfd-II). IncP-1β plasmids from the same field showed small deletions and/or insertions in accessory metabolic genes. One plasmid belonged to an unclassified plasmid group and carries a copy of both tfdA and tfd-II identical to those in the IncP-1β plasmids. Our results indicate intra-field evolution and inter-field exchange of 2,4-D-catabolic IncP-1β plasmids as well as the exchange of tfd genes between different plasmids within a confined local environment.

U2 - 10.1093/femsec/fiy214

DO - 10.1093/femsec/fiy214

M3 - Journal article

C2 - 30380047

AN - SCOPUS:85056611261

VL - 95

SP - 1

EP - 11

JO - F E M S Microbiology Ecology

JF - F E M S Microbiology Ecology

SN - 0168-6496

IS - 1

M1 - fiy214

ER -