Trichoderma: Harzianum Complex Clade Species in Soils of Central and South America: Revision and Distribution

As environmental and health concerns increase, the trend of sustainable agriculture moves toward using biological agents. About 60% of all biological fungicides have Trichoderma species as the active ingredient, with T. harzianum as the most common species in these products. However, the name T. harzianum has often been incorrectly used in culture collections, databases, and the scientific literature due to the division of the Harzianum Complex Clade (HCC) into more than 95 cryptic species with only one being named T. harzianum. In this study, 49 strains previously identified as T. harzianum in three surveys of Trichoderma species from soils in South and Central America were re-identified using phylogenetic analyses based on tef1α, rpb2, and ITS loci and were combined with the corresponding species in two other studies, where the species were correctly identified. Based on the results of the five surveys of the total 148 strains in HCC, 11 species were identified and T. afroharzianum, T. lentiforme, T. endophyticum followed by T. azedevio and T. harzianum were detected as the dominant species of the HCC in South and Central America. This is the first report of identifying dominant Trichoderma species within the HCC in South and Central American soil based on multiple studies, which will be useful in selecting strains within the complex clade for formulation of biocontrol and biofertilizer products in the continent.