TY - JOUR

T1 - Long-Range PCR Reveals the Genetic Cargo of IncP-1 Plasmids in the Complex Microbial Community of an On-Farm Biopurification System Treating Pesticide-Contaminated Wastewater

AU - Dunon, Vincent

AU - Holmsgaard, Peter N.

AU - Dealtry, Simone

AU - Lavigne, Rob

AU - Sørensen, Søren J.

AU - Smalla, Kornelia

AU - Top, Eva M.

AU - Springael, Dirk

N1 - Publisher Copyright: Copyright © 2022 American Society fo Microbiology. All Rights Reserved.

PY - 2022

Y1 - 2022

N2 - Promiscuous plasmids like IncP-1 plasmids play an important role in the bacterial adaptation to pollution by acquiring and distributing xenobiotic catabolic genes. However, most information comes from isolates and the role of plasmids in governing community-wide bacterial adaptation to xenobiotics and other adaptive forces is not fully understood. Current information on the contribution of IncP-1 plasmids in community adaptation is limited because methods are lacking that directly isolate and identify the plasmid borne adaptive functions in whole-community DNA. In this study, we optimized long-range PCR to directly access and identify the cargo carried by IncP-1 plasmids in environmental DNA. The DNA between the IncP-1 backbone genes trbP and traC, a main insertion site of adaptive trait determinants, is amplified and its content analyzed by high-throughput sequencing. The method was applied to DNA of an on-farm biopurification system (BPS), treating pesticide contaminated wastewater, to examine whether horizontal gene exchange of catabolic functions by IncP-1 plasmids is a main driver of community adaptation in BPS. The cargo recovered from BPS community DNA encoded catabolic but also resistance traits and various other (un)known functions. Unexpectedly, genes with catabolic traits composed only a minor fraction of the cargo, indicating that the IncP-1 region between trbP and traC is not a major contributor to catabolic adaptation of the BPS microbiome. Instead, it contains a functionally diverse set of genes which either may assist biodegradation functions, be remnants of random gene recruitment, or confer other crucial functions for proliferation in the BPS environment. IMPORTANCE This study presents a long-range PCR for direct and cultivation-independent access to the identity of the cargo of a major insertion hot spot of adaptive genes in IncP-1 plasmids and hence a new mobilome tool for understanding the role of IncP-1 plasmids in complex communities. The method was applied to DNA of an on-farm biopurification system (BPS) treating pesticide-contaminated wastewater, aiming at new insights on whether horizontal exchange of catabolic functions by IncP-1 plasmids is a main driver of community adaptation in BPS. Unexpectedly, catabolic functions represented a small fraction of the cargo genes while multiple other gene functions were recovered. These results show that the cargo of the target insertion hot spot in IncP-1 plasmids in a community, not necessarily relates to the main obvious selective trait imposed on that community. Instead, these functions might contribute to adaptation to unknown selective forces or represent remnants of random gene recruitment.

AB - Promiscuous plasmids like IncP-1 plasmids play an important role in the bacterial adaptation to pollution by acquiring and distributing xenobiotic catabolic genes. However, most information comes from isolates and the role of plasmids in governing community-wide bacterial adaptation to xenobiotics and other adaptive forces is not fully understood. Current information on the contribution of IncP-1 plasmids in community adaptation is limited because methods are lacking that directly isolate and identify the plasmid borne adaptive functions in whole-community DNA. In this study, we optimized long-range PCR to directly access and identify the cargo carried by IncP-1 plasmids in environmental DNA. The DNA between the IncP-1 backbone genes trbP and traC, a main insertion site of adaptive trait determinants, is amplified and its content analyzed by high-throughput sequencing. The method was applied to DNA of an on-farm biopurification system (BPS), treating pesticide contaminated wastewater, to examine whether horizontal gene exchange of catabolic functions by IncP-1 plasmids is a main driver of community adaptation in BPS. The cargo recovered from BPS community DNA encoded catabolic but also resistance traits and various other (un)known functions. Unexpectedly, genes with catabolic traits composed only a minor fraction of the cargo, indicating that the IncP-1 region between trbP and traC is not a major contributor to catabolic adaptation of the BPS microbiome. Instead, it contains a functionally diverse set of genes which either may assist biodegradation functions, be remnants of random gene recruitment, or confer other crucial functions for proliferation in the BPS environment. IMPORTANCE This study presents a long-range PCR for direct and cultivation-independent access to the identity of the cargo of a major insertion hot spot of adaptive genes in IncP-1 plasmids and hence a new mobilome tool for understanding the role of IncP-1 plasmids in complex communities. The method was applied to DNA of an on-farm biopurification system (BPS) treating pesticide-contaminated wastewater, aiming at new insights on whether horizontal exchange of catabolic functions by IncP-1 plasmids is a main driver of community adaptation in BPS. Unexpectedly, catabolic functions represented a small fraction of the cargo genes while multiple other gene functions were recovered. These results show that the cargo of the target insertion hot spot in IncP-1 plasmids in a community, not necessarily relates to the main obvious selective trait imposed on that community. Instead, these functions might contribute to adaptation to unknown selective forces or represent remnants of random gene recruitment.

KW - Adaptive traits

KW - Biopurification system

KW - Catabolic genes

KW - Genetic cargo

KW - Horizontal gene transfer

KW - IncP-1 plasmid

KW - Microbial community

U2 - 10.1128/aem.01648-21

DO - 10.1128/aem.01648-21

M3 - Journal article

C2 - 34878814

AN - SCOPUS:85124438152

VL - 88

JO - Applied and Environmental Microbiology

JF - Applied and Environmental Microbiology

SN - 0099-2240

IS - 3

M1 - e01648-21

ER -