Development of a real-time PCR assay for detection and quantification of Rhizobium leguminosarum bacteria and discrimination between different biovars in zinc-contaminated soil.

ABSTRACT: Primers were designed to target 16S rRNA and nodD genes of Rhizobium leguminosarum from DNA extracted from two different soil types contaminated with Zn applied in sewage sludge. Numbers of rhizobia estimated using 16S rRNA gene copy number showed higher abundance than those estimated by both nodD and the most-probable-number (MPN) enumeration method using a plant trap host. Both 16S rRNA gene copies and the MPN rhizobia declined with increased levels of Zn contamination, as did the abundance of the functional gene nodD, providing compelling evidence of a toxic effect of Zn on R. leguminosarum populations in the soil. Regression analysis suggested the total Zn concentration in soil as a better predictor of rhizobial numbers than both NH4NO3-extractable and soil solution Zn. R. leguminosaru

SUBMITTER: Macdonald CA 

PROVIDER: S-EPMC3127725 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature