Plant Defensive Responses Triggered by Trichoderma spp. as Tools to Face Stressful Conditions

The current agriculture is facing various challenges to produce enough food to satisfy the need of the human population consumption without having a negative impact on the environment, human health and ecosystems. The exploitation of bioinoculants has been a crucial alternative for green agriculture. Bioinoculants have two great benefits: to promote plant growth by making essential nutrients available to crops and, to increase the tolerance to biotic and abiotic stresses by inducing a long-lasting defense. Certain members of genus Trichoderma have been recognized as biocontrol agents, biofertilizers and stress alleviators for the plants. The use of Trichoderma spp. has also been extended to protect and stimulate growth of horticultural crops. Elucidating the plant signaling events triggered by Trichoderma is of high importance in order to understand the molecular basis involving plant protection against stresses. In this review, the signaling elements of the plants from Trichoderma perception through late defensive responses is discussed. Enhanced understanding how Trichoderma spp. activate defense will lead to improvement in the use of species of this genus to increase crop production with the consequent benefits for human health and care for the environment.