• Inoculation with AMF strengthen the peanut resistance to Cd stress. • AMF exhibited the promotion of seedling growth, enhancement of photosystem, activation of antioxidant systems, and maintenance of plasma membrane integrity, hence alleviating Cd stress. • AMF simulated the biosynthesis of crucial phytohormones and promoted the nutrient accumulations of peanut in response to Cd stress. • AMF-inoculated peanut plants exhibited enhanced Cd tolerance through modulating secondary metabolisms. Arbuscular mycorrhizal fungi (AMF) play dominant roles in crop abiotic stress resistance; however, research gaps still exist in ascertaining their specific effects on counteracting soil cadmium (Cd) contamination in legume crops. The current work utilized an integrated physiological, transcriptional, and metabolomic approach to investigate the functions of an AMF mixture-comprising Rhizophagus irregularis SA, Rhizophagus clarus BEG142, Glomus lamellosum ON393, and Funneliformis mosseae BEG95 (1: 1: 1: 1, w/w/w/w)-in alleviating peanut Cd stress. AMF-inoculated plants exhibited higher plant height, root length, plant biomass, and nitrogen content in roots and stems when the seedlings were exposed to Cd stress at 80 mg Cd kg −1 soil. Moreover, the photosynthetic rate, Fv/Fm, and chlorophyll content increased by 36.04%, 21.79%, and 58.39%, respectively, in functional leaves under Cd stress. AMF also increased the activities of antioxidant enzymes, reduced the accumulation of reactive oxygen species, and maintained the integrity of the cell membrane in response to Cd. Additionally, osmotic regulatory substances such as sucrose and free amino acids were dramatically increased by 21.13% and 31.13%, respectively, in AMF-inoculated peanut roots subjected to Cd stress. Multi-omics analyses revealed that AMF modulated genes and metabolites associated with several key pathways, including phytohormone biosynthesis, the TCA cycle, and the metabolism of nitrogen, starch, sucrose, and flavonoids in Cd-stressed peanut roots. Taken together, this study demonstrated that AMF play vital roles in enhancing peanut Cd tolerance through promoting plant growth, protecting photosystem, strengthening the antioxidant system, modulating phytohormones (e.g., auxin, gibberellin, and cytokinin), and modifying nitrogen, and carbon, flavonoid metabolism.
Wang et al. (Wed,) studied this question.