Molecular characterization of novel Bradyrhizobium strains nodulating Eriosema chinense and Flemingia vestita, important unexplored native legumes of the sub-Himalayan region (Meghalaya) of India

Archana Ojha, Nisha Tak, Sonam Rathi, Bhawana Chouhan, Satyawada Rama Rao (Lead / Corresponding author), Saroj K. Barik, Santa R. Joshi, Janet S. Sprent, Euan K. James, Hukam Singh Gehlot

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Root nodule bacterial strains were isolated from the little-studied legumes Eriosema chinense and Flemingia vestita (both in tribe Phaseoleae, Papilionoideae) growing in acidic soil of the sub-Himalayan region of the Indian state of Meghalaya (ME), and were identified as novel strains of Bradyrhizobium on the basis of their 16S rRNA sequences. Seven isolates selected on the basis of phenotypic characters and assessment of ARDRA and RAPD patterns were subjected to multilocus sequence analysis (MLSA) using four protein-coding housekeeping genes (glnII, recA, dnaK and gyrB). On the basis of 16S rRNA phylogeny as well as a concatenated MLSA five strains clustered in a single separate clade and two strains formed novel lineages within the genus Bradyrhizobium. The phylogenies of the symbiotic genes (nodA and nifH) were in agreement with the core gene phylogenies. It appears that genetically diverse Bradyrhizobium strains are the principal microsymbionts of these two important native legumes. The novel genotypes of Bradyrhizobium strains isolated in the present study efficiently nodulate the Phaseoloid crop species Glycine max, Vigna radiata and Vigna umbellata. These strains are genetically different from strains of Bradyrhizobium isolated earlier from a different agro-climatic region of India suggesting that the acidic nature of the soil, high precipitation and other local environmental conditions are responsible for the evolution of these newly-described Bradyrhizobium strains. In global terms, the sub-Himalayan region of India is geographically and climatically distinct and the Bradyrhizobium strains nodulating its legumes appear to be novel and potentially unique to the region.

Original languageEnglish
Pages (from-to)334-444
Number of pages11
JournalSystematic and Applied Microbiology
Volume40
Issue number6
Early online date19 Jul 2017
DOIs
Publication statusPublished - Sep 2017

Keywords

  • Journal article
  • Flemingia vestita
  • Eriosema chinense
  • Meghalaya (ME)
  • Bradyrhizobium
  • Housekeeping genes
  • Multilocus sequence analysis (MLSA)

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