A phylogenetic and taxonomic re-evaluation of the Bipolaris - Cochliobolus - Curvularia Complex

• Published in: Fungal diversity Vol. 56; no. 1; pp. 131 - 144
• Main Authors: Manamgoda, Dimuthu S., Cai, Lei, McKenzie, Eric H. C., Crous, Pedro W., Madrid, Hugo, Chukeatirote, Ekachai, Shivas, Roger G., Tan, Yu Pei, Hyde, Kevin D.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.09.2012
• Subjects: alignment; Biodiversity; Biomedical and Life Sciences; Bipolaris; Cochliobolus; Curvularia; fungi; genes; genus; helminthosporium; Life Sciences; Medical Microbiology; Microbial Ecology; Microbiology; Mycology; pathogens; Plant Physiology; Poaceae; pseudocochliobolus; rdna; sequences; species concepts; Anamorph; Neotype; Pathogens; Nomenclature; Generic complex
• ISSN: 1560-2745; 1878-9129
• DOI: 10.1007/s13225-012-0189-2

Three genera, Cochliobolus , Bipolaris and Curvularia form a complex that contains many plant pathogens, mostly on grasses ( Poaceae ) with a worldwide distribution. The taxonomy of this complex is confusing as frequent nomenclatural changes and refinements have occurred. There is no clear morphological boundary between the asexual genera Bipolaris and Curvularia , and some species show intermediate morphology. We investigated this complex based on a set of ex-type cultures and collections from northern Thailand. Combined gene analysis of rDNA ITS (internal transcribed spacer), GPDH (glyceraldehyde 3-phosphate dehydrogenase), LSU (large subunit) and EF1-α (translation elongation factor 1-α) shows that this generic complex divides into two groups. Bipolaris and Cochliobolus species clustered in Group 1 along with their type species, whereas Curvularia species (including species named as Bipolaris , Cochliobolus and Curvularia ) clustered in Group 2, with its generic type. The nomenclatural conflict in this complex is resolved giving priority to the more commonly used established generic names Bipolaris and Curvularia . Modern descriptions of the genera Bipolaris and Curvularia are provided and species resolved in this study are transferred to one of these genera based on their phylogeny.