Abstract
Curvularia is a Pleosporalean monophyletic genus with a great diversity of species, including relevant phytopathogenic, animal and human pathogenic fungi. However, their microscopic identification is difficult due to overlapping morphological features amongst species. In recent years, multi-locus sequence analysis using the ITS region of the rDNA and fragments of the genes gapdh and tef1 revealed numerous cryptic species, especially in isolates that commonly produced 3-septate conidia. Therefore, based on sequence analysis of the above-mentioned DNA barcodes recommended for species delineation in Curvularia, we propose three novel species, C. paraverruculosa, C. suttoniae and C. vietnamensis, isolated from soil, human clinical specimens and plant material, respectively, collected in different countries. These new species are morphologically characterised and illustrated in the present study. Curvularia paraverruculosa differs from its counterparts, C. americana and C. verruculosa, mainly by its narrower conidia. Curvularia suttoniae and C. vietnamensis are closely related to C. petersonii, but the former two have larger conidia.
Highlights
The genus Curvularia Boedijn (1933), typified by C. lunata (Wakker) Boedijn, belongs in Pleosporaceae, Pleosporales (Wijayawardene et al 2018)
Sutton of the Fungus Testing Laboratory at the University of Texas Health Sciences Center (UTHSC; San Antonio, USA) and the other three (FMR 11956, FMR 17656, FMR 17659) were isolated from environmental samples; the first from sorghum seeds collected in Indonesia, the second from soil collected in the Mexican region of Michoacán and the third from unidentified plant material collected in the north-east of Vietnam
BLASTn results with gapdh sequences showed that the isolate FMR 17656 was ≤ 97.6%, similar to C. verruculosa CPC 28792; FMR 11956 and FMR 17659 showed a similarity of 93.31% and 93.6%, respectively, with C. spicifera CBS 198.31; and isolates FMR 10992 and FMR 11690 both exhibited a similarity of 94.7% with the ex-type strain of C. petersonii (BRIP 14642)
Summary
The genus Curvularia Boedijn (1933), typified by C. lunata (Wakker) Boedijn, belongs in Pleosporaceae, Pleosporales (Wijayawardene et al 2018). Members of Curvularia show different life modes, i.e. saprophytic, endophytic and pathogenic on plants and animals (Marin-Felix et al 2017a). Since the first report of Curvularia as a human pathogen in a patient with mycetoma (Baylet et al 1959), other clinical presentations have been reported, such as superficial and deep infections that mainly affect the respiratory tract but can even cause cerebral phaeohyphomycosis with an extremely poor prognosis (de Hoog et al 2000)
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