Trichoderma as biostimulant: exploiting the multilevel properties of a plant beneficial fungus

Plant biostimulants are formulated with diverse microorganisms and/or substances that are applied to crops with the aim of enhancing growth, development and adaptation to abiotic stress. Trichoderma-based products have been particularly successful because of their capacity to control phytopathogenic fungi. Some Trichoderma strains have a predominant biostimulant action that makes them unique for their extended use in horticulture. They are safe for humans, livestock and crop plants and in their natural environment colonize plant roots without apparent adverse reactions. Both solid and liquid formulations containing conidia can be used to produce suitable quantities of active and viable inocula during product formulation and field use. The mechanism of phytostimulation by Trichoderma involves multilevel communication with root and shoot systems, as it releases into the rhizosphere auxins, small peptides, volatiles and other active metabolites, which promote root branching and nutrient uptake capacity, thereby boosting plant growth and yield. Recent proteomic and genetic data suggest that Trichoderma activates the mitogen activated protein kinase 6, transcription factors and DNA processing. proteins, which represent promising targets toward formulation of more efficient products. (C) 2015 Elsevier B.V. All rights reserved.