Trichoderma-Plant Association Enhances Plant Antioxidant Capacity and Tolerance to Abiotic Stresses

The soil fungus Trichoderma, and products based on effective strains thereof, is commonly used for disease biocontrol in horticulture and agriculture. Additionally, recent reports indicate that these fungi may also induce resistance to abiotic stresses. In order to better understand this phenomenon and use its potentials to improve crop production, we have studied its effects on germination and early seedling growth of tomato under various abiotic stresses. Treated seeds germinated consistently faster and more uniformly than untreated seeds whether the stress was osmotic, salt or suboptimal temperatures. The consistent response to varying stresses suggests a common mechanism through which the plant-fungal association enhances tolerance to a wide range of abiotic stresses. Redox state of the major non-enzymatic antioxidant molecules in T22-treated seedlings germinated in control conditions or under osmotic stress is enhanced in both roots and shoots of treated plants compared to untreated plants, especially under osmotic stress. Effects of plant-Trichoderma association on expression and activity of enzymes involved in recycling oxidized glutathione and ascorbate and other antioxidant enzymes and their importance in evolution of activated oxygen molecules and prevention of molecular and cellular damage will be discussed. The importance of these findings in better understanding of the molecular basis of this symbiotic relationship and its implication to improve seedling performance under stress has substantial commercial potential beyond current uses.