Molecular phylogeny and morphology reveal three novel species of Curvularia (Pleosporales, Pleosporaceae) associated with cereal crops and weedy grass hosts

Authors: FERDINANDEZ, HIMASHI - University Of Sri Jayewardenepura; MANAMGODA, DIMUTHU - University Of Sri Jayewardenepura; UDAYANGA, DHANUSHKA - University Of Sri Jayewardenepura; DESHAPPRIYA, NELUM - University Of Sri Jayewardenepura; MUNASINGHE, MAYURI - University Of Sri Jayewardenepura; Castlebury, Lisa

Submitted to: Mycological Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2021
Publication Date: 4/18/2021
Citation: Ferdinandez, H.S., Manamgoda, D.S., Udayanga, D., Deshappriya, N., Munasinghe, M.S., Castlebury, L.A. 2021. Molecular phylogeny and morphology reveal three novel species of Curvularia (Pleosporales, Pleosporaceae) associated with cereal crops and weedy grass hosts. Mycological Progress. 20:431–451. https://doi.org/10.1007/s11557-021-01681-0.
DOI: https://doi.org/10.1007/s11557-021-01681-0

Interpretive Summary: Fungi in the genus Curvularia occur on many different plant hosts with many species causing significant diseases on cereals. Because many species in this genus have similar microscopic appearances, they are often difficult to identify correctly. In this study, species of Curvularia were isolated from grass hosts in Sri Lanka and compared with other species from all over the world and characterized using DNA sequences and cultural characteristics. Three new species were discovered and described with images provided. This research will be used by extension agents, plant breeders, plant pathologists, and plant quarantine officials to implement management strategies and to accurately determine the presence of these species around the world and to keep American agriculture safe.

Technical Abstract: The genus Curvularia comprises phytopathogenic, saprobic, epiphytic and endophytic fungal species associated with cereal crops and their wild relatives. Recently, multi-locus phylogenetic studies have been widely implemented for accurate identification of Curvularia, at the species level. Although the genus is taxonomically diverse, the species associated with cereal crops and weeds are poorly known in Sri Lanka. In this study, symptomatic specimens of cereals and associated weedy grass hosts were collected from selected locations in Sri Lanka. The isolates obtained were initially identified based on microscopic characters. The nuclear ribosomal internal transcribed spacers 1 and 2 with 5.8S region (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and translation elongation factor 1-a (TEF1) loci were sequenced and used in multi-locus phylogenetic analyses. Three novel evolutionary lineages were identified, distinct from all the currently accepted species of Curvularia. To accommodate the novel phylogenetic lineages, three novel species of Curvularia are described, namely Curvularia eleusinicola, C. panici-maximi and C. simmonsii. Morphological descriptions and illustrations are provided for the newly described taxa. In addition, host records are updated for recently introduced C. plantarum and C. pseudointermedia. This study highlights the need for extensive collections and molecular identifications of tropical species of hyphomycetous fungi associated with cereals, fibre crops and weeds in order to support effective disease management and surveillance measures.