Interactive Effect of Arbuscular Mycorrhizal Fungi (AMF) and Olive Solid Waste on Wheat under Arsenite Toxicity.

Heavy metal such as arsenite (As) is a threat worldwide. Thus, to mitigate As toxicity on plants, we investigated the interactive effect of olive solid waste (OSW) and arbuscular mycorrhizal fungi (AMF) on wheat plants under As stress. To this end, wheat seeds were grown in soils treated with OSW (4% ), AMF-inoculation, and/or As treated soil (100 mg/kg soil). AMF colonization is reduced by As but to a lesser extent under As + OSW. AMF and OSW interactive effects also improved soil fertility and increased wheat plants' growth, particularly under As stress. The interactions between OSW and AMF treatments reduced As-induced HO accumulation. Less HO production consequently reduced As-related oxidative damages i.e., lipid peroxidation (malondialdehyde, MDA) (58%), compared to As stress. This can be explained by the increase in wheat's antioxidant defense system. OSW and AMF increased total antioxidant content, phenol, flavonoids, and α-tocopherol by approximately 34%, 63%, 118%, 232%, and 93%, respectively, compared to As stress. The combined effect also significantly induced anthocyanins accumulation. The combination of OSW+AMF improved antioxidants enzymes activity, where superoxide dismutase (SOD, catalase (CAT), peroxidase (POX), glutathione reductase (GR), and glutathione peroxidase (GPX) were increased by 98%, 121%, 105%, 129%, and 110.29%, respectively, compared to As stress. This can be explained by induced anthocyanin percussors phenylalanine, cinamic acid and naringenin, and biosynthesic enzymes (phenylalanine aminolayse (PAL) and chalcone synthase (CHS)). Overall, this study suggested the effectiveness of OSW and AMF as a promising approach to mitigate As toxicity on wheat growth, physiology, and biochemistry.