Enhancing Trichoderma efficacy in managing wheat stem rust disease and boosting production through the application of...

Wheat stem rust (WSR), caused by Puccinia graminis f. sp. tritici (Pgt), represents a significant threat to global wheat production. Biocontrol agents, such as Trichoderma harzianum HE22 (TH), offer sustainable strategies for managing this disease. This study evaluates the efficacy of TH cultured in potato dextrose broth (PDB) supplemented with various chemical inducers (TSDCIS), including potassium tartrate (T1), a mixture of micronutrients (T2), and thiamine (T3). These treatments were compared to unmodified TH (T4) to evaluate their potential in controlling WSR at both the seedling stage and under field conditions, with the primary objective of enhancing disease management while improving wheat yield and quality.

Under both greenhouse and field conditions, T1 significantly reduced disease severity by 86.2% and 77.7%, respectively, and decreased the area under the disease progress curve (AUDPC) by 77.5% compared to the untreated control. T1 also extended the incubation and latent periods, reduced pustule density, and mitigated oxidative damage. Biochemical analyses revealed elevated levels of total phenols and enhanced activity of antioxidant enzymes, including peroxidase (POD) and polyphenol oxidase (PPO), along with increased concentrations of ascorbic acid and proline. Additionally, T1 reduced lipid peroxidation, lowered H₂O₂ concentrations, and minimized electrolyte leakage, demonstrating its protective effects on plant tissues. Microscopic analyses using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) confirmed these protective effects. Treated plants exhibited intact cellular membranes, well-organized chloroplasts, and enhanced cellular integrity, whereas untreated plants showed severe structural damage, including plasmolysis and distorted chloroplast morphology.

T. harzianum HE22 supplemented with potassium tartrate (T1) demonstrates significant potential as an environmentally friendly and highly effective strategy for managing wheat stem rust. This approach not only reduces disease severity but also enhances wheat yield and overall plant health, making it a promising tool for sustainable agricultural practices.