Integrated in vitro and computational approaches reveal stress gene expression and protein function in Trichoderma strains isolated from tannery contaminated soil

Understanding the mechanisms of heavy metal tolerance in fungi is essential for their potential application in bioremediation. This study investigates the biochemical and molecular responses of Trichoderma strains isolated from leather industrial areas under cadmium, chromium, copper, and lead stress using integrated in vitro and computational approaches. Results of the in vitro experiments revealed that Trichoderma atrobrunneum exhibited significant tolerance to high metal concentrations, as indicated by its high tolerance index (TI) and metal uptake capacity (Cr > Pb > Cu > Cd) as compared to the other strains. The antioxidant defense system, including CAT, POX, and SOD, demonstrated enhanced enzymatic activity under metal stress, suggesting activation of oxidative stress responses. Total protein content increased significantly in all treatments, indicating stress-induced protein synthesis. The enzymatic activity and protein content were enhanced mainly in T. atrobrunneum. Gene expression analysis through qPCR confirmed the upregulation of stress-responsive genes, including HSP70, POX, SOD, and MT, with variations in expression levels across different metals and Trichoderma strains i.e. T. atrobrunneum showed significant upregulation of the selected genes, while T. viride showed downregulation of MT genes for Cr, Cd and Cu stress. Computational annotation using UniProt and QuickGO validated the functional roles of these proteins in ATP binding, protein folding, ROS (Reactive oxygen species) detoxification, and metal ion sequestration. Integrating in vitro data and in silico analysis provided thorough insights into the molecular mechanisms of gene regulation underlying heavy metal tolerance, proposing Trichoderma strains as effective bioremediation agents to address high-concentration heavy metal pollution, particularly for the reclamation of agricultural soil polluted with heavy metals.