Trichoderma: Harzianum Clade in Soils from Central and South America

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