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Title: THE TRICHODERMA KONINGII MORPHOLOGICAL SPECIES

Author
item Samuels, Gary
item DODD, SARAH - NEW ZEALAND
item LU, BINGSHENG - CHINA
item PETRINI, ORLANDO - SWITZERLAND
item SCHROERS, HANS-JOSEF - THE NETHERLANDS
item DRUZHININA, IRINA - AUSTRIA

Submitted to: Studies in Mycology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/24/2006
Publication Date: 9/15/2006
Citation: Samuels, G.J., Dodd, S., Lu, B., Petrini, O., Schroers, H., Druzhinina, I. S., 2006. The Trichoderma Koningii Morphological Species. Studies in Mycology. 56:67-133.

Interpretive Summary: Fungi often live in or on plants. Some fungi can be destructive causing diseases of plants while others can be useful because they help plants fight the organisms that cause plant diseases. Fungi that are called Trichoderma are especially good at controlling plant diseases. In order to use fungi to control diseases, it is necessary to determine exactly which kinds or species of Trichoderma are most effective. Distinguishing between species of Trichoderma is complicated because these fungi are very small and do not have a lot of different shapes and colors. In this research information about their genome is used to precisely define species of Trichoderma. Within one group of Trichoderma, thirteen different species are defined. A description and illustrations of each species are presented along with a key to help people identify each species. Detailed analyses of how the fungi look and grow as well as their geographic distribution are used to distinguish these species. These species vary in biological characteristics such as whether they exist in the living leaves or trunk of plants and their ability to control diseases. Based on the genomic data, a unique molecular sequence or DNA barcode was determined for each species so that other scientists can easily identify them. This research will be used by plant pathologists who are working to control diseases to accurately identify these fungi.

Technical Abstract: Trichoderma koningii is among the most commonly cited species in the genus. The morphological species Trichoderma koningii can be considered to be stereotypical of Trichoderma, viz. conidiophore with a more or less conspicuous main axis from which often paired lateral branches arise, the branches increasing in length with distance from the tip of the main axis and themselves branch in the same manner. As is the case with most Trichoderma species, conidia are ellipsoidal to oblong, smooth, and green. Teleomorphs of fungi having the ‘koningii’ morphology are very similar to the teleomorph of T. viride (Hypocrea rufa) and are not discriminatory, or are marginally discriminatory, of species. Ascospores are hyaline, stromata are at first semieffused, tan and villose but may become tuberculate, pulvinate to discoidal and brown to red-brown, ostiolar openings are typically not visible or at most barely visible on the stroma surface. Phylogenetic analysis utilizing partial sequences of the translation-elongation factor 1 alpha (tef1), as well as fragments of actin and calmodulin genes, indicate that morphological characters typical of T. koningii evolved independently in two well-separated main lineages with no fewer than fourteen phylogenetic species. Multivariate analysis of phenotype characters combined with patterns of geographic distribution of members of clades supported the phylogenetic analysis. Combined molecular and phenotype data lead to the development of a taxonomy with the recognition of twelve taxonomic species and one variety. The few phenotype characters that were useful in species recognition include growth rate, colony characters and conidium size and morphology. Despite many reports of its widespread distribution, T. koningii s. str. was found to be an uncommon species restricted to Europe and eastern North America; it is redescribed. Isolates of T. caribbaeum var. aequatoriale, T. koningiopsis, and T. ovalisporum were isolated as endophytes of trunks of Theobroma species in tropical America and T. ovalisporum was isolated also as an endophyte from the woody liana Banisteropsis caapi that was infected with Crinipellis perniciosa in Ecuador. Trichoderma koningiopsis was found to be common in tropical America but was isolated also from natural substrata in East Africa, Europe and Canada, and from ascospores in eastern North America. Several additional new species, which are known only from their teleomorphs, are T. austrokoningii, T. dingleyae, T. dorotheae, from Australia and New Zealand; T. petersenii, T. rogersonii from eastern North America and western Europe; T. intricatum is known from two teleomorph collections respectively from the Caribbean and Thailand and T. taiwanense is known from a single teleomorph collection made in Taiwan. Isolates of T. ovalisporum and T. koningiopsis may have biological control potential. A classical morphophenetic key and a set of tools for molecular species identification were developed.