Trichoderma Species from Semiarid Regions and Their Antagonism Against the Microorganisms That Cause Pepper Wilt

Chili wilt is a significant challenge in producing jalapeño peppers, which has led to the implementation of strategies to help counteract or combat the microorganisms responsible for it. One of these strategies is the use of biological control microorganisms, such as <i>Trichoderma</i>, a fungus recognized as a natural enemy of the microorganisms that cause chili wilt. Therefore, this study aimed to isolate and identify <i>Trichoderma</i> species from the soils and roots of different plants, and evaluate their antagonism against <i>Rhizoctonia solani</i>, <i>Phytophthora capsici</i>, and <i>Fusarium</i> sp. Due to the complexity in identifying <i>Trichoderma</i> at the species level, performing a multilocus phylogenetic analysis was necessary, using the ITS, RPB2, and TEF1 regions. The species isolated were <i>T. afroharzianum</i>, <i>T. lentiforme</i>, <i>T. rifaii</i>, <i>T. brevicompactum</i>, <i>T. arundinaceum</i>, and <i>T. longibrachiatum</i>. Subsequently, they were used in three antagonism tests (dual culture, non-volatile organic compounds, and volatile organic compounds) against the phytopathogenic microorganisms. The tests demonstrated that the <i>Trichoderma</i> isolates could inhibit the mycelial growth of all three tested pathogens, obtaining the best results with the strains <i>T. brevicompactum</i> (19RCS), <i>T. lentiforme</i> (63DPS), <i>T. longibrachiatum</i> (71JES), <i>T. rifaii</i> (77JCR), and <i>T. afroharzianum</i> (24RQS, 87CCS, 88CCS and 17RCS). The strain with the best results in all three tests was 17RCS.