Cruz-Magalhães, ValterPadilla-Arizmendi, FabiolaHampton, JohnMendoza - Mendoza, ArtemioHorwitz, BAMukherjee, PK2023-05-232022-06-092022-06-099789811695063https://hdl.handle.net/10182/16146Trichoderma fungi are facultative plant symbionts that colonize multiple plant species. In natural environments, the process of root colonization by Trichoderma involves several stages. The first is the capacity of Trichoderma to colonize the rhizosphere by sensing molecules secreted by the roots, and the ability to compete or cooperate with the microbial community present in the rhizosphere. Once Trichoderma reaches the rhizoplane, the fungus must next overcome/manipulate the innate plant defenses by releasing secreted molecules which will allow its establishment inside the root. During this process of rhizosphere and root colonization, Trichoderma release specialized metabolites (commonly known as secondary metabolites) that manipulate the roots and also restrict bacteria, nematodes, and filamentous pathogens. The impact of Trichoderma in agriculture relies on the capacity to combat the negative effects of plant pathogens, and the ability to induce resistance in plant tissues far from the site of colonization (induced systemic resistance, ISR). ISR is activated by the sensing of Trichoderma elicitors and does not require root colonization. Here, we describe the different components as well as the impact of Trichoderma on the rhizosphere microbiome, the mechanisms of root colonization, and ISR activation.pp.235-272, 12 chapters© 2022 The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Trichodermamicrobiomerhizosphererhizosphere competencedisease suppressive soilsendophytesspecialised metabolitesinduced-systemic resistanceendophytic continuumplant defensemycoparasitismBook Chapter10.1007/978-981-16-9507-0_102523-8450978-981-16-9507-02023-05-22