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Some Candida species that were similar in phenotypic characteristics were studied by molecular taxonomic comparisons including electrophoretic karyotypes, DNA base composition, and DNA relatedness. Among the species studied, Candida terebra, Candida entomaea, and Candida veronae showed similar electrophoretic karyotypes and a G + C range from 39.7 to 40.2 mol% in DNA base composition, and demonstrated 85–104% DNA similarity on the basis of flourometric hybridization in microdilution wells. As C. terebra has priority, we suggest that C. entomaea and C. veronae should be synonyms of C. terebra. Other species in this study, Candida dendronema, Candida diddensiae, Candida naeodendra, and Candida atmospherica, had low DNA relatedness. Thus, these species should be maintained in their original separate taxa.Key words: DNA reassociation, electrokaryotype, Candida species, synonym.

Strain W-10, originally identified as Trichoderma koningii, and its supposed mutant G-39, published for production and gene expression of cellulase and xylanase, demonstrated morphological characteristics distinct from those of T. koningii, respectively. To clarify the identification derived from morphological characteristics, several methods were used, including electrophoretic karyotyping, internal transcribed spacer (ITS) analysis of rDNA, and polymerase chain reaction (PCR) fingerprinting using the universal primer L45. All the molecular characteristics showed that strains G-39 and W-10 were identical to T. reesei and T. longibrachiatum, respectively. The results strongly supported that T. koningii G-39 and W-10 should be reassigned as T. reesei and T. longibrachiatum, respectively. Strain G-39 should be considered a mutant from T. reesei QM9414 whose spores were contaminated with those of strain W-10 during a laboratory operation. According to this, we declare that T. koningii G-39 and W-10 must be renamed as T. reesei and T. longibrachiatum, respectively.Key words: PCR fingerprinting, electrophoretic karyotypes, ITS, Trichoderma.

Molecular approaches including internal transcribed spacer (ITS) sequences of ribosomal DNA, universal primer polymerase chain reaction (UP-PCR) fingerprinting, and DNA–DNA hybridization were used to study the genetic relatedness of species within Trichoderma sect. Pachybasium. In the analysis of ITS and 5.8S sequences of ribosomal DNA, parsimony analysis demonstrated that forty-one strains were distributed into five main groups supported by high bootstrap values. The species of Trichoderma sect. Pachybasium were clustered into groups I, II, and IV, with the strains of Trichoderma fasculatum and Trichoderma strictipile forming a separate branch, an independent group V. Some species within each group showed nearly identical sequence differences (fewer than 1–3 bp). UP-PCR and DNA–DNA hybridization were further used to clarify the genetic relatedness of these species with highly similar ITS sequences. Highly similar or identical UP-PCR profiles and high values of DNA complementarity (>70%) were observed among some species, Trichoderma hamatum and Trichoderma pubescens; Trichoderma croceum,Trichoderma polysporum and Trichoderma album; Trichoderma crassum and Trichoderma flavofuscum; and Trichoderma strictipile and Trichoderma fasciculatum. Although every species can be differentiated morphologically, the species showed highly similar molecular characteristics in the above cases, indicating that they could be conspecific. However, in some cases (Trichoderma longipile, T. crassum and T. flavofuscum; Trichoderma fertile and Trichoderma minutisporum; Trichoderma tomentosum, Trichoderma inhamatum and Trichoderma harzianum) there were discriminative patterns of UP-PCR and (or) low levels (