New species and records of Bipolaris and Curvularia from Thailand

Abstract

Several Bipolaris and Curvularia spp. were collected from different disease symptoms of Poaceae in Thailand. Phylogenetic analyses based on DNA sequence data of the internal transcribed spacer region and intervening 5.8S nrRNA gene, and partial fragments of the glyceraldehyde-3-phosphate dehydrogenase and the translation elongation factor 1-α genes, demonstrated that these isolates represent one new species of Bipolaris, B. brachiariae, and five new species of Curvularia, i.e. C. chiangmaiensis, C. dactyloctenicola, C. nodosa, C. pseudobrachyspora, and C. variabilis. Bipolaris brachiariae is related to B. heliconiae, B. maydis, and B. saccharicola, but produces shorter conidiophores and conidia. Curvularia chiangmaiensis is characterized by very long conidiophores to 2 mm. Curvularia dactyloctenicola is closely related to C. chiangmaiensis, but can easily be distinguished by the size of its conidiophores and conidia. Curvularia nodosa is related to C. hawaiiensis and C. dactyloctenii, but it produces abundantly knotted hyphae, which were not observed in the other two species, as well as shorter conidia with fewer septa. Curvularia pseudobrachyspora is related to C. brachyspora, but differs in the size of its conidiophores. Finally, Curvularia variabilis can be easily distinguished by its highly variable conidia. Furthermore, the description of B. oryzae is emended to include two isolates belonging to this species from Thailand that produce much longer conidiophores and conidia with fewer septa than observed in previous descriptions. The present study is also the first report of Bipolaris bicolor, B. setariae and B. yamadae from Thailand. Moreover, new hosts are reported for B. bicolor (Eleusine indica), B. setariae (Imperata cylindrica), and Curvularia verruculosa (Eleusine indica).

Cryptic species of Curvularia in the culture collection of the Queensland Plant Pathology Herbarium

“…Curvularia beasleyi is distinguished in two loci from the ex-type cultures of C. dactyloctenii (99% in gapdh and 99% in tef1α ), C. hawaiiensis (98% in gapdh and 99% in tef1α ) and C. nodosa (99% in gapdh and 99% in tef1α ). The conidia of C. beasleyi are longer than those of C. nodosa (12–25 µm, Marin-Felix et al 2017b) and shorter than those of C. dactyloctenii (32–55 µm, Sivanesan 1987). Curvularia beasleyi is morphologically similar to C. hawaiiensis , however the later species has never been recorded on Leersia (Farr and Rossman 2018).…”

“…1). Curvularia dactyloctenii and C. hawaiiensis have been recorded in Australia (Sivanesan 1987, Tan et al 2014), but the recently described C. nodosa has only been reported from Thailand (Marin-Felix et al 2017b). Curvularia beasleyi is distinguished in two loci from the ex-type cultures of C. dactyloctenii (99% in gapdh and 99% in tef1α ), C. hawaiiensis (98% in gapdh and 99% in tef1α ) and C. nodosa (99% in gapdh and 99% in tef1α ).…”

“…There are many Curvularia species reported as associated with Chloris spp. ( C. australiensis , C. australis, C. hawaiiensis , C. lunata , C. nodosa , C. pallescens , C. tsudae , C. variabilis , C. verruculosa ) (Sivanesan 1987, Deng et al 2014, Manamgoda et al 2014, Marin-Felix et al 2017b) and Leersia spp. ( C. australiensis , C. geniculata , and C. heteropogonicola ) (DAF Biological Collections 2018, Farr and Rossman 2018, Herbarium Catalogue 2018), although not all of the reports have been verified by molecular phylogenetic analyses.…”

“…Curvularia is a species-rich genus of pathogens and saprobes associated with plant, human and animals worldwide (Sivanesan 1987, Hyde et al 2014, Madrid et al 2014, Manamgoda et al 2015, Marin-Felix et al 2017a, b). Curvularia species have also been reported from substrates such as air (Almaguer et al 2012, Hargreaves et al 2013), aquatic environments (Verma et al 2013, Su et al 2015, Sharma et al 2016) and soil (Manamgoda et al 2011, Marin-Felix et al 2017a).…”

“…Currently, there are 131 species of Curvularia (excluding varieties) listed in Index Fungorum (accessed on 4 January 2018). Phylogenetic studies based on multilocus sequence analyses of ex-type or reference cultures have recently delimited many cryptic species (Deng et al 2014, Manamgoda et al 2014, Tan et al 2014, Manamgoda et al 2015, Marin-Felix et al 2017a, 2017b). Presently, there are 81 accepted species for which taxonomic placement has been established by DNA barcodes to allow accurate identification and comparison (Marin-Felix et al 2017a, b).…”