Lead toxicity induced phytotoxic effects on mung bean can be relegated by lead tolerant Bacillus subtilis (PbRB3). (November 2019)

• Record Type: Journal Article
• Authors: Arif, Muhammad Saleem; Yasmeen, Tahira; Shahzad, Sher Muhammad; Riaz, Muhammad; Rizwan, Muhammad; Iqbal, Shahid; Asif, Muntaha; Soliman, Mona H.; Ali, Shafaqat
• Is Part Of: Chemosphere. Volume 234(2019)
• Page Start: 70
• Page End: 80
• Publication Date: 2019-11
• Subjects: Metal contamination -- Legume -- Oxidative stress -- Biosorption -- Microbial inoculant; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.06.024
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Being a primary toxic heavy metal, lead (Pb) contamination presents an imposing environmental and public health concern worldwide. A Bacillus subtilis PbRB3, displaying higher Pb tolerance, was isolated from the textile effluent. The bacterial culture was able to remove >80% of Pb from culture solution. Upon screening in the presence of Pb, PbRB3 strain exhibited significant plant growth promoting potential. A 3 weeks long pot experiment was established to examine the capability of PbRB3 strain for physiological and biochemical traits, and Pb accumulation tendency of mung bean at 250 and 500 mg kg −1 of Pb toxicity, respectively. With respect to control treatments, photosynthetic pigments, protein synthesis, net assimilation rate, transpiration rate and stomatal conductance were significantly constrained by Pb toxicity levels. Intrinsic and instantaneous water use efficiencies were considerably improved in inoculated plants under Pb toxicity. Compared to inoculated control, significantly higher superoxide dismutase activity in both Pb toxicity treatments, while higher malondialdehyde contents only at Pb500 treatment was recorded with PbRB3 inoculation. Catalase activity between Pb250 and Pb500 treatments was comparable at both inoculation level. Moreover, PbRB3 inoculation led to significantly higher peroxidase activity under Pb toxicity treatments compared to inoculated control. The PbRB3 inoculation led to comparable differences in root Pb content between Pb250 and Pb500 treatments. These results suggest that inoculation of Pb tolerant, Bacillus subtilis PbRB3, could be employed to improve mung bean growth potential and adaptation against Pb toxicity, and thereby accelerated Pb rhizoaccumulation from metal contaminated environment. Highlights: A Bacillus subtilis PbRB3 was isolated from textile effluent. PbRB3 removed >80% of Pb from spiked culture solution. Photosynthetic pigments impaired by Pb toxicity even upon inoculation. PbRB3 improved plant water use efficiency at Pb250 and Pb500. PbRB3 mediated Pb translocation from root to aerial part.