Polyphasic and functional diversity of high altitude culturable Bacillus from rhizosphere of Eleusine coracana (L.) Gaertn.

Abstract Soil structures and composition of the high Himalayan tracts are known as “biodiversity hotspots”, which enhance our understanding on the ecology of the rhizospheric microflora such as aerobic endospore forming Bacillus species. Increasing altitude gradient of these slopes is uniquely (district Uttarkashi) known for their deficient agricultural output. In such scenario, the local economy is supported by the cultivation of food security crop Eleusine coracana L. (Ragi) that leads to sustainability in the regiospecific conundrum. Five separate ecological zones were selected for sampling from this high altitude region to assess the diversity of Bacillus population associated with Ragi. A total of 48 Bacillus isolates were obtained from the rhizosphere of Ragi and further analyzed on functional approaches for diversity assessment from this low agricultural output and ecologically-fragile zone. Ecological assumptions based on phenotypic and metabolic diversities were bereft with similar limitations among the Ragi associated aerobic endospore forming bacilli; however, this is where functionally diverse Bacillus spp. hold significance, particularly in relation to evergreen and sustainable agriculture of high altitude hills. The study concludes that the site specific diversity (based on the Simpson and Shannon-Wiener indices) and density of culturable bacteria (log cfu g −1 ) are in positive correlation along with the increasing gradient of altitude with respect to the Ragi crop. Abundance of the species Bacillus cereus and Paenibacillus spp. was observed based on 16S rDNA sequencing. Studies highlight higher abundance of functionally diverse bacilli contrary to the harsh terrain.