Molecular systematics of the dimorphic ascomycete genus Taphrina

• Published in: International journal of systematic and evolutionary microbiology Vol. 53; no. 2; pp. 607 - 616
• Main Authors: Rodrigues, Manuel G, Fonseca, Alvaro
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.03.2003; Society for General Microbiology
• Subjects: Ascomycota - classification; Ascomycota - genetics; Bacteriology; Biological and medical sciences; DNA, Ribosomal - analysis; DNA, Ribosomal - genetics; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Microbiology; Miscellaneous; Molecular Sequence Data; Mycology; Phylogeny; Phytopathology. Animal pests. Plant and forest protection; Plants - microbiology; Polymerase Chain Reaction; RNA, Bacterial - analysis; Systematics; Transcription, Genetic; Fungi; Ascomycetes; Taphrina; Thallophyta
• ISSN: 1466-5026; 1466-5034
• DOI: 10.1099/ijs.0.02437-0

Centro de Recursos Microbiológicos (CREM), Secção Autónoma de Biotecnologia, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica, Portugal Correspondence Álvaro Fonseca amrf{at}fct.unl.pt The ascomycete genus Taphrina Fries comprises nearly 100 species recognized by their mycelial states when parasitic on different vascular plants. Whereas the filamentous state is strictly phytoparasitic, the yeast state is saprobic and can be cultured on artificial media. Taphrina species are differentiated mainly on the basis of host range and geographical distribution, type and site of infection and morphology of the sexual stage in infected tissue. However, there has been little progress in the systematics of the genus in recent years, mainly because of the scarcity of molecular studies and available cultures. The main aim of the present study was the reappraisal of species boundaries in Taphrina based on the genetic characterization of cultures (yeast states) that represent about one-third of the currently recognized species. The molecular methods used were (i) PCR fingerprinting using single primers for microsatellite regions and (ii) determination of nucleotide sequences of two approx. 600 bp nuclear rDNA regions, the 5' end of the 26S rRNA gene (D1/D2 domains) and the internal transcribed spacer region (which includes the 5.8S rRNA gene). Sequencing results confirmed the monophyly of the genus (with the probable exclusion of Taphrina vestergrenii ) and the combined analysis of the two methods corroborated, in most cases, separation of species defined on the basis of conventional criteria. However, genetic heterogeneity was found within some species and conspecificity was suggested for strains that have been deemed to represent distinct species. Sequences from the ITS region displayed a higher degree of divergence than those of the D1/D2 region between closely related species, but were relatively conserved within species (>99 % identity) and were thus more useful for the effective differentiation of Taphrina species. The results further allowed other topics to be addressed such as the correlation between the molecular phylogenetic clustering of certain species and the respective host plant family and the significance of molecular methods in the accurate diagnosis of the different diseases caused by Taphrina species. Abbreviations: ITS, internal transcribed spacer; MSP-PCR, microsatellite-primed PCR fingerprinting Published online ahead of print on 9 August 2002 as DOI 10.1099/ijs.0.02437-0. The GenBank accession numbers of sequences determined in this study are AF492024 – AF492075 (D1/D2) and AF492076 – AF492129 and AF494056 (ITS). A dendrogram resulting from analysis of combined MSP-PCR banding patterns is available as supplementary material in IJSEM Online ( http://ijs.sgmjournals.org ).