Submitted to: Mycologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 20, 2008
Publication Date: February 24, 2009
Repository URL: http://hdl.handle.net/10113/27641
Citation: Samuels, G.J., Ismaiel, A.A. 2009. Trichoderma evansii and T. lieckfeldtiae: two new T. hamatum-like species. Mycologia. 101:142-156. Interpretive Summary: Fungi in the genus Trichoderma are effective in the biological control of plant diseases including those that attack cacao trees, the source of chocolate, in South America and Africa. Development of these biological control agents is hindered by lack of species that can effectively control specific diseases. Many species of Trichoderma occur as endophytes inside healthy living plants. In this research two new species of Trichoderma were discovered inside the woody tissue of trees in Peru and Cameroon. These new species were named, described, and illustrated and their closest relatives determined. This research will be used by plant pathologists working to control diseases of cacao and other crop plants in South America and Africa.
Technical Abstract: The new species Trichoderma evansii and T. lieckfeldtiae resemble the closely related T. hamatum and T. pubescens in forming discrete, setose conidial pustules within which arise smooth, green conidia from pachybasium-like conidiophores. The phylogenetic position of these species was determined using combined partial sequences of ITS, translation-elongation factor 1-alpha, RNA polymerase II subunit, and actin genes. All are members of the Viride clade. Trichoderma evansii forms a sister-group relationship with a clade that includes T. hamatum and T. pubescens. It differs from the latter two species in having subglobose conidia; it was isolated as an endophyte from sapwood of Lophira alata (Ochnaceae) and Cola verticillata (Malvaceae) in Cameroon and Theobroma gileri (Malvaceae) in Peru. Trichoderma lieckfeldtiae occupies an unresolved position in the Viride clade despite being virtually morphologically indistinguishable from T. hamatum; it was isolated from brooms of cacao infected with Moniliophthora perniciosa in Colombia, pseudostroma of Moniliophthora roreri on pods of Theobroma cacao in Peru, and from soil in a cacao farm in Cameroon (Central Africa).