Synergistic effect of PGPR and PSB for alleviation of chromium toxicity in Vigna radiata (L.) R. Wilczek seedlings

NOVELTY STATEMENTThe present research work suggests the combined potential of PGPR and PSB in agriculture and can be adopted as a sustainable strategy for the alleviation of Cr toxicity stress in mining soil THE NOVELTY, SCIENTIFIC SIGNIFICANCE AND IMPORTANCE OF THE RESULTThe present invitro hydroponic study is an novel alternative phytotechnological approach of using a combined application of PGPR and PSB for remediation/mitigation of Cr pollution. The synergistic role of PGPR and PSB in developing Cr-induced stress tolerance in green gram seedlings is depicted. The implication of these two tools significantly alleviates the Cr toxicity stress in green gram and effectively increased the growth of the plant in a stressed condition. The combined treatment of PGPR and PSB represents an improved strategy for the amelioration of chromium toxicity in green gram. The present research work suggests the combined potential of PGPR and PSB in agricultural and can be adopted as a sustainable strategy for the alleviation of Cr toxicity stress in mining soil. This suggest the possible application of PGPR and PSB as an effective tool for the bioremediation of Cr and growing green gram crops in chromium-contaminated areas. In this way, it can also contribute some plantation practices for the growth and survival of plants in contaminated sites and minimizing the perilous impact of chromium on the soil. The current investigation depicts the individual and synergistic effects of two important plant growth promoting microbial groups viz. Plant Growth Promoting Rhizobacteria (PGPR) and Phosphate Solubilizing Bacteria (PSB) in alleviating the phytotoxic impacts of chromium in Vigna radiata (L) R. Wilczek (green gram) seedlings. Cr6+ (100 ppm) treatment caused a stiff decline of about 44%, 72%, 68%, and 49% reduction in root and shoot length as well as leaf number and leaf area respectively as compared to control after 90 d of exposure. However, combined amendment with PGPR and PSB causes a significant amelioration of Cr toxicity though doubling the shoot length and leaf area with a 4 times increase in root length and leaf number after 90 d of growth. Total chlorophyll synthesis showed a 68% reduction in Cr6+ (100 ppm) which was ameliorated by combined treatments of PGPR and PSB. It showed a 123% increased total chlorophyll content than Cr6+ (100 ppm) whereas individual application of PGPR and PSB showed a 46% and 27% increase respectively. Combined application of PGPR and PSB with a toxic dose of Cr showed significant boosting alleviation ability and indicates its ameliorative role for abatement of Cr-induced toxicity.