Aspergillus Welwitschiae Regulates Response of Wheat at Multiple Levels To Alleviate Induced Chromate Stress

Chromium (Cr) pollution from anthropogenic activities threatens agriculture and food security in developing countries, necessitating sustainable bioremediation strategies to mitigate its effects. In the current study, Aspergillus welwitschiae, a Cr-tolerant fungus, accumulated > 50% Cr from Czapek broth and improved wheat immunity to tolerate up to 75 ppm of chromate in soil. Inoculation with A. welwitschiae significantly improved Triticum aestivum L. (wheat) tolerance to chromate stress (75 ppm) in the growth medium. The fungal association modulated phytohormone levels, increasing endogenous salicylic acid (SA) (68.5%), indole acetic acid (IAA) (97.14%), and gibberellic acid (GA₃) (34.13%). Additionally, inoculated plants exhibited elevated levels of key metabolites, including flavonoids (94.9%), phenols (13.8%), and soluble sugars (21.3%). Oxidative stress markers like malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) declined by 4.28-fold and 2.36-fold, respectively, compared to non-inoculated controls. The strain also enhanced activities of the antioxidative enzyme under Cr stress, with catalase, and peroxidase levels increasing by 3.67-, and 6.26-folds at 75 ppm Cr. Furthermore, A. welwitschiae promoted Cr uptake and translocation in wheat, accumulating ~ 1.6-fold more Cr in aerial tissues, demonstrating its efficacy in soil remediation for chromium-contaminated agricultural systems.