Mitigating the negative effects of lead toxicity on Vigna mungo: The promising role of rhizobacteria

Growing Vigna mungo in soils contaminated with lead (Pb) is a major concern due to its negative impact on plant growth and development. When lead enters through food in the human body, it can be accumulated in bones, liver, and kidneys. In severe cases, lead poisoning can cause cancer, seizures, coma, and even death. To address this issue in plants, phosphate-solubilizing bacteria (PSB) have been identified as a potential solution to enhance plant growth and mitigate the harmful effects of heavy metal toxicity. However, the effectiveness of PSB can be improved by isolating and characterizing new strains over time, which will aid in developing sustainable management strategies for Pb-contaminated soils. Thus, the current study aimed to investigate the impact of Pb contamination on V. mungo growth and the potential use of newly isolated microbial strains to enhance V. mungo growth and immobilize Pb. Three levels of Pb contamination were used: control (no Pb toxicity), 125Pb (125 mg Pb/kg soil), and 250Pb (250 mg Pb/ kg soil). Six different microbial strains, RP01, RP02, RP03, RP04, RP05, and RP06, were used to inoculate V. mungo seeds. The results of the experiment demonstrated that RP02 was the most effective strain in improving various growth parameters such as shoot length, root length, seedling length, fresh weight, dry weight, chlorophyll a, chlorophyll b, and total chlorophyll. While RP03 also showed significant improvement in these growth parameters, its effectiveness was not as high as RP02 in some respects. The efficacy of RP02 in alleviating Pb toxicity was further confirmed by a significant decrease in Pb concentration in the seedling, which was attributed to the production of siderophore. Therefore, it can be concluded that RP02 has the potential to improve V. mungo growth under Pb contamination. However, further field investigations are needed to confirm RP02 as the best strain for enhancing V. mungo production under Pb toxicity.(c) 2023 The Authors. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).