ISSN 2736-1756
Advanced Journal of Microbiology Research ISSN 2241-9837 Vol. 14 (4), pp. 001-007, April, 2020. © International Scholars Journals
Full Length Research Paper
Transposon mutant of Vigna radiata-nodulating Bradyrhizobium sp. impaired in both resistance to stress conditions and symbiotic performance
Neelawan Pongsilp1* and Nantakorn Boonkerd2
1Department of Microbiology, Faculty of Science, Silpakorn University-Sanam Chandra Place Campus, Nakhon Pathom, Thailand.
2School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand.
Accepted 16 September, 2019
Abstract
Rhizobial strains that nodulate Vigna radiata (mungbean) were examined for their resistance to several stress conditions. One strain of mungbean rhizobia was selected to construct a collection of transposon mutants based on resistance to high temperature (40°C), alkalinity (pH 8.0) and several heavy metals. One mutant that is deficient in resistance to high temperature, alkalinity and zinc was selected to estimate the relation between resistance to stress conditions and symbiotic performance. Southern hybridization analysis showed a single transposon insertion in the mutant strain. The impaired symbiotic performance was observed in the host plants inoculated with the mutant strain as compared with the wild-type strain. This result suggested that genes involved in stress resistance affected the symbiotic ability. The 16S rDNA sequence analysis revealed that the strain is a member of Bradyrhizobium with 98% identity.
Key words: Bradyrhizobium, mutant, transposon, stress tolerance, symbiosis.