Antagonistic potential and functional diversity of endo and rhizospheric bacteria of basmati rice

A total of 150 plant growth promoting rhizobacteria (PGPR) were isolated from endo- and rhizospheric soil of five varieties of basmati rice viz. Pusa Sugandha-4, Sugandha-5, HBC-19, Super Basmati and Punjab Basmati grown in fields of IARI, New Delhi. All these isolates were characterized for functional traits like nitrogen fixation, P-solubilization, auxin production, siderophore production, HCN production, in vitro bioassay against plant pathogenic fungi and bacteria. Varietal influence was observed on the population number of PGPR in basmati rice. Variety HBC-19 supported high frequency of endophytes and fluorescent pseudomonads, however, Super Basmati showed the highest number of isolates from rhizosphere. Nearly 50% of isolates inhibited the fungal (Sclerotium rolfsii, Fusarium oxysporum and Rhizoctonia bataticola) and bacterial pathogens (Xanthomonas compestris pv phaseoli M5, Xanthomonas oryzae, Xanthomonas compestris pv phaseoli CP-1-1 and Ralstonia solanacerum) but showed low frequency for other functional traits. None of the isolates nodulated the seven legumes tested. The best strains identified for auxin production, P-solubilization and siderophore production were UKA-24, UKA-27 and UKA-72 and identified as Rhizobium radiobacter, Bacillus pumillus and Stenotrophomonas maltophila respectively.