Direct biostimulation and biocontrol properties of Trichoderma species. Beneficial Trichoderma spp. exert fungal-root communication via diffusible and volatile compounds, regulation of the stress hormone ethylene, and production of phytohormones, such as auxins (indole-3-acetic acid). Some of the plant-protecting mechanisms of Trichoderma include parasitism, antibiotic and secondary metabolites production, or activation of the induced systemic resistance (ISR). Trichoderma can trigger both growth-stimulating effects and plant defense action by the elicitation of salicylic acid (SA), ethylene (ET), and jasmonic acid (JA) dependent pathways against several types of potential plant pathogens such as nematodes and fungi.