Malate-mediated CqMADS68 enhances aluminum tolerance in quinoa seedlings through interaction with CqSTOP6, CqALMT6 and CqWRKY88

Aluminum (Al) stress in acidic soils has severe negative effects on crop productivity. In this study, the alleviating effect and related mechanism of malate on Al stress in quinoa (Chenopodium quinoa) seedlings were investigated. The findings indicated that malate alleviated the growth inhibition of quinoa seedlings under Al stress, maintained the enzymatic and nonenzymatic antioxidant systems, and aided resistance to the damage caused by excessive reactive oxygen species (ROS). Under Al stress, malate significantly increased the contents of chlorophyll and carotenoids in quinoa shoots by 103.8% and 240.7%, and significantly increased the ratios of glutathione (GSH)/oxidized glutathione (GSSG), and ascorbate (AsA)/dehydroascorbate (DHA) in roots by 59.9% and 699.2%, respectively. However, malate significantly decreased the superoxide radical (O