Biochemical and molecular characterization of a rhizobitoxine-producing Bradyrhizobium from pigeon pea plants.
Out of a total of 8 bacterial strains isolated from the root nodules of pigeon pea plants grown in arid region, five were identified as rhizobia based on biochemical test and confirmed by 16S rDNA sequencing. PCR based screening for the rtxA gene (involved in biosynthesis of rhizobitoxine) revealed that the gene was present in one strain identified biochemically and genetically as belonging to species Bradyrhizobium (BS KT-24). The strain was resistant to phosphomycin, nalidixic acid, kanamycin, gentamicin and neomycin but sensitive towards streptomycin and spectinomycin. Bioinformatic-tool-guided phylogenetic analysis of rtxA gene revealed its distinctiveness from other known rtxA genes (present in B. japonicum, B. elkanii and Xanthomonas oryzae). The rhizobitoxine producing strain BS KT-24 is considered to exhibit better survival and nodulation protection besides competitiveness for pigeon pea and other legumes grown under abiotic stress and, thus, be a candidate in practical aspect of rhizobitoxine production by rhizobium and its application as rhizobial inoculants.
Kanika
Plant-Microbe Interaction Laboratory, National Research Centre on Plant Biotechnology, New Delhi, 110012, India. kumarkanika@rediffmail.com
Dogra
Tripti
T
Lata
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D020369:Bradyrhizobium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D036561:Cajanus / Q000382:microbiology*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology; D016133:Polymerase Chain Reaction; D011412:Propanolamines / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D000637:Transaminases / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D011412:Propanolamines; D012336:RNA, Ribosomal, 16S; D000637:Transaminases; C041618:rhizobitoxine