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( R,S )‐dichlorprop herbicide in agricultural soil induces proliferation and expression of multiple dioxygenase‐encoding genes in the indigenous microbial community
Author(s) -
Paulin Mélanie M.,
Nicolaisen Mette H.,
Sørensen Jan
Publication year - 2011
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/j.1462-2920.2011.02456.x
Subject(s) - biology , dioxygenase , gene , microbial population biology , gene expression , soil microbiology , temperature gradient gel electrophoresis , microcosm , sphingomonas , genetics , microbiology and biotechnology , bacteria , 16s ribosomal rna , ecology
Summary We investigated the effect of ( R,S )‐dichlorprop herbicide addition to soil microcosms on the degrading indigenous microbial community by targeting multiple α‐ketoglutarate‐dependent (α‐KG) dioxygenase‐encoding genes ( rdpA , sdpA and tfdA group I) at both gene and transcript level. The soil microbial community responded with high growth of potential degraders as measured by the abundance of dioxygenase‐encoding genes using quantitative real‐time PCR (qPCR). rdpA DNA was not detectable in unamended soil but reached over 10 6 copies g −1 soil after amendment. sdpA and tfdA were both present prior to amendment at levels of ∼5 × 10 4 and ∼10 2 copies g −1 soil, respectively, and both reached over 10 5 copies g −1 soil. While expression of all three target genes was detected during two cycles of herbicide degradation, a time‐shift occurred between maximum expression of each gene. Gene diversity by denaturing gradient gel electrophoresis (DGGE) uncovered a diversity of sdpA and tfdA genes at the DNA level while rdpA remained highly conserved. However, mRNA profiles indicated that all transcribed tfdA sequences were class III genes while rdpA transcripts shared 100% identity to rdpA of Delftia acidovorans MC1 and sdpA transcripts shared 100% identity to sdpA from Sphingomonas herbicidovorans MH. This is the first report to describe expression dynamics of multiple α‐KG dioxygenase‐encoding genes in the indigenous microbial community as related to degradation of a phenoxypropionate herbicide in soil.