Integrated N-acetylcysteine-microbial based phytostabilization mitigates lead (Pb) contamination and limits its...

Lead (Pb) contamination of agricultural soils poses a serious threat to ecosystem stability, crop productivity, and human health due to its transfer through the food chain. Developing sustainable strategies to immobilize Pb in soil while maintaining crop productivity is therefore critical for food safety. In this study, we evaluated the effectiveness of integrating a heavy metal-tolerant plant growth-promoting (HMT-PGP) microbial consortium (MC) with exogenous N-acetyl cysteine (NAC, 200 μM) to mitigate Pb stress in a soil-plant (wheat) system. A pot experiment was conducted under Pb contamination levels of 250 and 500 mg kg^-1. The combined application (MC + NAC) significantly improved soil health by enhancing nutrient availability, enzymatic activities, and beneficial microbial populations by 7.3-37.2%, 10.7-53%, and 15-60%, respectively. These improvements were accompanied by enhanced photosynthetic performance and antioxidant defense, resulting in reduced oxidative stress indicators such as proline accumulation and chlorophyll-carotenoid imbalance. Consequently, wheat plants treated with microbial consortium and NAC exhibited ∼48% higher biomass and ∼36% greater chlorophyll content compared with Pb-stressed controls. Importantly, the combined treatment significantly reduced Pb accumulation in roots and shoots (32.7-52.9%) and markedly limited Pb translocation to grains (52.9-54%). Enhanced root endophyte colonization further contributed to improved plant tolerance under Pb stress. Overall, these findings demonstrate that integrating HMT-PGP microbes with NAC represents an effective and environmentally sustainable strategy to stabilize Pb in contaminated soils, improve wheat productivity, and reduce heavy-metal entry into the human food chain.