Optimizing soybean (Glycine max (L.) (PS 1347) seed protein accumulation under lead stress through mycorrhizal fungi mediation

Lead is among the most toxic and harmful heavy metals to living things, including plants. It is absorbed through roots from soil and causes several detrimental impacts on plant functioning. The present study aimed to elucidate the ameliorative effects of arbuscular mycorrhizal (AM) fungi on soybean (Glycine max (L.) variety PS 1347) under lead (Pb) stress by investigating growth parameters, yield attributes, and seed protein characteristics. Following established legume Pb tolerance thresholds and soil Pb limits, Pb (as Pb(NO3)2) was introduced into soil-filled polybags at three concentrations: 200, 500, and 700 mg/kg of soil. In addition to inoculating polybags with AM fungi Glomus mosseae and G. fasciculatum, both individually and in combination, the fungi were utilized for seed priming Vesicular Arbuscular Mycorrhiza (VAM) powder, 25g/kg of seeds. Without AM fungi, Pb stress negatively impacted all growth parameters, yield metrics, and seed protein characteristics. At 200 and 500 mg Pb concentrations, individual Glomus species exhibited greater effectiveness in enhancing plant growth and yield attributes and mitigating Pb effects, while dual Glomus species treatment was more effective in improving the soybean growth characteristics with higher Pb concentration (700 mg). The analysis also showed that Pb toxicity in soybean plants decreased seed protein content to 7 %, which was restored by applications of Glomus treatments. Thus, given their pivotal role in optimizing soybean seed protein quantity and quality, these two AM fungal species are recommended for application to enhance plant performance in Pb-affected soil.