Mitigation of arsenic toxicity in wheat by the inoculation of methyltransferase containing Pseudomonas oleovorans NBRI-B4.10

Abstract

Arsenic (As) pollution in croplands is a significant global environmental issue. Being the dominant irrigated crop, rice is the main focus for research related to arsenic toxicity, however, wheat being the basic staple food has not been studied well. Therefore, the present study sought to investigate the potential of arsenic-tolerant rhizobacteria for its mitigation in wheat. Ten As tolerant bacterial strains were characterized for abiotic stress tolerance, antibiotic resistance, and plant growth-promoting traits. Methyltransferase containing Pseudomonas oleovorans (NBRI-B4.10) with a better arsenic tolerance index (151.74%) in wheat outperformed the other strains. In vitro study, showed the highest phosphate solubilization ability (40.17 μgmL⁻¹) under As⁺⁵ (250 μgmL⁻¹) stressed condition in NBRI-P media, accompanied with more As biosorption (72.9%) in culture pellet, confers the As detoxification ability of B4.10 during arsenic-phosphate (As–P) interaction too. Organic acid production studied during the process of P-solubilization by methyltransferase bacteria, NBRI-B4.10 reveals the production of higher concentrations of gluconic and tartaric acid at As⁺⁵ (25 μgmL⁻¹) stress. Furthermore, NBRI-B4.10 inoculation increased the plant growth and nutrient content (Se) while decreasing As content in grain (∼53.3%) leading to arsenic abatement in wheat.