TY - JOUR
T1 - Plasmids pJP4 and r68.45 can be transferred between populations of bradyrhizobia in nonsterile soil
AU - Kinkle, B. K.
AU - Sadowsky, M. J.
AU - Schmidt, E. L.
AU - Koskinen, W. C.
PY - 1993
Y1 - 1993
N2 - IncP plasmid r68.45, which carries several antibiotic resistance genes, and IncP plasmid pJP4, which contains genes for mercury resistance and 2,4- dichlorophenoxyacetic acid degradation, were evaluated for their ability to transfer to soil populations of rhizobia. Transfer of r68.45 was detected in nonsterile soil by using Bradyrhizobium japonicum USDA 123 as the plasmid donor and several Bradyrhizobium sp. strains as recipients. Plasmid transfer frequencies ranged up to 9.1 x 10-5 in soil amended with 0.1% soybean meal and were highest after 7 days with strain 3G4b4-RS as the recipient. Transconjugants were detected in 7 of 500 soybean nodules tested, but the absence of both parental strains in these nodules suggests that plasmid transfer had occurred in the soil, in the rhizosphere, or on the root surface. Transfer of degradative plasmid pJP4 was also evaluated in nonsterile soil by using B. japonicum USDA 438 as the plasmid donor and several Bradyrhizobium sp. strains as recipients. Plasmid pJP4 was transferred only when strains USDA 110-ARS and 3G4b4-RS were the recipients. The plasmid transfer frequency was highest for strain 3G4b4-RS (up to 7.4 x 10-6). Mercury additions to soil, ranging from 10 to 50 μg/g of soil, did not affect population levels of parental strains or the plasmid transfer frequency.
AB - IncP plasmid r68.45, which carries several antibiotic resistance genes, and IncP plasmid pJP4, which contains genes for mercury resistance and 2,4- dichlorophenoxyacetic acid degradation, were evaluated for their ability to transfer to soil populations of rhizobia. Transfer of r68.45 was detected in nonsterile soil by using Bradyrhizobium japonicum USDA 123 as the plasmid donor and several Bradyrhizobium sp. strains as recipients. Plasmid transfer frequencies ranged up to 9.1 x 10-5 in soil amended with 0.1% soybean meal and were highest after 7 days with strain 3G4b4-RS as the recipient. Transconjugants were detected in 7 of 500 soybean nodules tested, but the absence of both parental strains in these nodules suggests that plasmid transfer had occurred in the soil, in the rhizosphere, or on the root surface. Transfer of degradative plasmid pJP4 was also evaluated in nonsterile soil by using B. japonicum USDA 438 as the plasmid donor and several Bradyrhizobium sp. strains as recipients. Plasmid pJP4 was transferred only when strains USDA 110-ARS and 3G4b4-RS were the recipients. The plasmid transfer frequency was highest for strain 3G4b4-RS (up to 7.4 x 10-6). Mercury additions to soil, ranging from 10 to 50 μg/g of soil, did not affect population levels of parental strains or the plasmid transfer frequency.
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U2 - 10.1128/aem.59.6.1762-1766.1993
DO - 10.1128/aem.59.6.1762-1766.1993
M3 - Article
C2 - 16348953
AN - SCOPUS:0027213381
SN - 0099-2240
VL - 59
SP - 1762
EP - 1766
JO - Applied and environmental microbiology
JF - Applied and environmental microbiology
IS - 6
ER -