Comparative overview of red kidney bean (Phaseolus valgaris) rhizospheric bacterial diversity in perspective of altitudinal variations

Red kidney bean (RKB) is an important cash crop of the Western Indian Himlayan (WIH) regions. Despite of having a long cultivation history, very little has known about its rhizospheric microbial diversity, which is becoming important for employing sustainable agricultural plans. In this perspective, the bacterial diversity and community structure of Himalayan RKB rhizosphere were studied and compared across the altitudinal zones of WIH. Metagenomic analysis revealed that Proteobacteria (31%) was the major phylum with the dominance of the genera Sphingomonas in the Garhwal while Pseudomonas in the Kumaun regions of Western Indian Himalaya (WIH), followed by Bacteroidetes (20%), Fermicutes (9%), Acidobacteria (7%), Actinobacteria (6%), Chloroflexi (5%), Gemmatimonadetes (3%) and Planctomyces (2%). Furthermore, the Garhwal soil was found to harbor more bacterial diversity than the Kumaun with unique genera Conexibacter, Ornithobacterium, Lacibacter, Salinibacter, Fervidicola, Haliangium, Pirellula, Caloramator, Desulfitobacterium, Edaphobacter, Holophaga and Massilia. The principal component analysis revealed that the bacterial diversity was associated with the content of “total solids” as well as “volatile acids” present in the respective soils. Additionally, large number of unclassified clone sequences suggesting the need of culture dependent studies to trap “yet not cultivated” bacterial species. Conclusively, the present study provides an overview of RKB associated bacterial diversity which must be explored for sustainable hill agricultural plans.