Significance of Bacillus subtilis strain SJ-101 as a bioinoculant for concurrent plant growth promotion and nickel accumulation in Brassica juncea.
In this study, a nickel (Ni)-tolerant Bacillus subtilis strain SJ-101 was characterized based on the 16SrDNA homology and phylogenetic analysis. The role of this strain ascertained in facilitating Ni accumulation in the Indian mustard plant (Brassica juncea [L]. Czern and Coss) var. Pusa Bold (DIR-50), to elucidate the potential of Ni phytoremediation in combination with metal-tolerant rhizobacteria. The data revealed that the plants exposed to NiCl2 (1750 mg kg(-1)) in soil bioaugmented with strain SJ-101 have accumulated 0.147% Ni vis-à-vis 0.094% accumulation in dry biomass of the plants grown in uninoculated soil. The strain SJ-101 has also exhibited the capability of producing indole acetic acid (IAA) (55 microg ml(-1)), and solubilizing inorganic phosphate (90 microg ml(-1)) in specific culture media. The pot culture experiments clearly demonstrated the beneficial effects of bioinoculant strain SJ-101 with significant increase (p<0.05) in the plant growth attributes in untreated control soil. Furthermore, the protective effect of the strain SJ-101 against Ni phytotoxicity was evident in plants grown in soil treated with NiCl2 in concentration range of 250-1750 mg kg(-1). Thus, it is suggested that the strain SJ-101 owing to its intrinsic abilities of plant growth promotion, and attenuation of soil Ni by biosorption and bioaccumulation, could be exploited for bacteria-assisted phytoaccumulation of this toxic heavy metal from contaminated sites.
Zaidi
Sabina
S
Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University (AMU), Aligarh 202 002, India.
Usmani
Saima
S
Singh
Braj Raj
BR
Musarrat
Javed
J
D001412:Bacillus subtilis / Q000378:metabolism*; D001937:Brassica / Q000254:growth & development* / Q000378:metabolism / Q000382:microbiology*; D007210:Indoleacetic Acids / Q000378:metabolism; D009532:Nickel / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012987:Soil
D007210:Indoleacetic Acids; D012987:Soil; C030737:indoleacetic acid; D009532:Nickel