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Title: TAXONOMY AND BIOCONTROL POTENTIAL OF A NEW SPECIES OF TRICHODERMA FROM THE AMAZON BASIN OF SOUTH AMERICA.

Author
item HOLMES, KEITH - CABI, UNITED KINGDON
item SCHROERS, HANS JOSEF - CBS, THE NETHERLANDS
item THOMAS, SARAH - CABI, UNITED KINGDOM
item EVANS, HARRY - CABI, UNITED KINGDOM
item Samuels, Gary

Submitted to: Mycological Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2004
Publication Date: 9/18/2004
Citation: Holmes, K.A., Schroers, H., Thomas, S.E., Evans, H.C., Samuels, G.J. 2004. Taxonomy and biocontrol potential of a new species of Trichoderma from the Amazon basin of South America. Mycological Progress. 3(3):199-210.

Interpretive Summary: Fungi in the genus Trichoderma are effective in the biological control of plant diseases. However, their development is hindered by lack of accurate systematic knowledge. In this research a survey was made for isolates of Trichoderma in Ecuador and Brazil that have potential to control the two major diseases of the chocolate tree. A new species of Trichoderma was discovered and is named, described and illustrated. This fungus was tested for its effectiveness in controlling the diseases of the chocolate tree and was found to slow down the growth of the pathogen that causes frosty pod rot. This research serves as the basis for the a method to control one of the most serious diseases of the chocolate tree.

Technical Abstract: The new species Trichoderma ovalisporum is described and its biocontrol potential against Crinipellis species is analyzed. Using partial nuclear translation elongation factor 1a (EF-la) and partial nuclear actin gene intron and exon sequences, T. ovalisporum is identified as a member of Trichoderma sect. Trichoderma and as a close relative of T. koningii-like taxa that have ellipsoidal to oblong, smooth conidia. Sequences of the internal transcribed spacer regions 1 and 2 (ITS) of the nuclear ribosomal gene cluster did not resolve the phylogeny of T. ovalisporum and its closest relatives. Trichoderma ovalisporum is morphologically similar to T. koningii, Hypocrea stilbohypoxyli, and three as yet undescribed Trichoderma taxa. It differs from its close relatives in having smaller, ovoidal conidia and in its fast rate of growth at 30°C. Trichoderma ovalisporum was isolated twice: once from witches' broom (Crinipellis perniciosa)-infected tissue of a liana (Banisteriopsis caapi, Malpighiaceae) collected in Ecuador. The second isolation was from the healthy bole of a mature tree of Theobroma grandiflorum (cupuaçu, Malvaceae) collected in Brazil (Pará). The liana isolate reinfected and was reisolated from meristematic tissues of seedlings of Theobroma cacao, and inhibited radial growth of the frosty pod rot pathogen (Crinipellis roreri) in vitro. It also persisted on the surface, and within the tissues, of cocoa pods in the field for at least 10 weeks.