Multi-locus phylogeny and taxonomy of Exserohilum

Abstract

Exserohilum includes a number of plant pathogenic, saprobic and clinically relevant fungi. Some of these species are of great importance in human activities, but the genus has never been revised in a phylogenetic framework. In this study, we revise Exserohilum based on available ex-type cultures from worldwide collections, observation of the holotypes and/or protologues, and additional isolates from diverse substrates and geographical origins. Based on nine nuclear loci, i.e., ITS, LSU, act, tub2, cam, gapdh, his, tef1 and rpb2, as well as phenotypic data, the genus and species boundaries are assessed for Exserohilum. Three species, i.e., E. novae-zelandiae, E. paspali and E. sorghicola, are excluded from the genus and reallocated in Sporidesmiella and Curvularia, respectively, whereas E. heteropogonicola and E. inaequale are confirmed as members of Curvularia. Exserohilum rostratum is revealed as conspecific with species previously described in Exserohilum such as E. antillanum, E. gedarefense, E. leptochloae, E. longirostratum, E. macginnisii and E. prolatum. Additionally, E. curvatum is revealed as synonym of E. holmii, and E. fusiforme of E. oryzicola. A total of 11 Exserohilum phylogenetic species are described, illustrated and discussed, including one novel taxon, E. corniculatum. The placements of 15 other doubtful species are discussed, and E. elongatum is validated.

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

“…Hernández-Restrepo et al 2018). The protein-coding loci of gapdh , tef1α and RNA polymerase II second largest subunit ( rpb2 ) have been reported as phylogenetically informative in the phylogenetic analyses of sequence data from species of Curvularia (Hernández-Restrepo et al 2018, Manamgoda et al 2014, Marin-Felix et al 2017a, 2017b).…”

“…Hernández-Restrepo et al 2018). The protein-coding loci of gapdh , tef1α and RNA polymerase II second largest subunit ( rpb2 ) have been reported as phylogenetically informative in the phylogenetic analyses of sequence data from species of Curvularia (Hernández-Restrepo et al 2018, Manamgoda et al 2014, Marin-Felix et al 2017a, 2017b). In this study, sequences of three loci (ITS, gapdh and tef1α ) from 17 cultures in BRIP were compared with those from ex-type cultures as well as published reference cultures for species of Bipolaris and Curvularia .…”

Exserohilum infections in Australian Queensland children

“…However, there is a growing population of at‐risk immunocompromised children and adults, leading to the emergence of less common but medically important fungal pathogens . All reviewed cases isolated E. rostratum which is the only Exserohilum species known to cause human disease …”

“…This dematiaceous mould is typically found in tropical climates and is a known plant pathogen . Recent phylogenetic analysis has shown five Exserohilum species to be synonyms of Exserohilum rostratum and includes two other species, Exserohilum mcginnisii and Exserohilum longirostratum , previously linked to human disease . Exserohilum rostratum was the causative organism in the 2012 outbreak and, due to the phylogenetic changes, is now the only reported Exserohilum species associated with human disease .…”

Diseases of Cymbopogon citratus (Poaceae) in China: Curvularia nanningensis sp. nov.

“…In order to accurately identify our strains, phylogenetic analysis included all ex-type and published strains of all Curvularia spp. described recently (Hyde et al 2017;Marin-Felix et al 2017;Dehdari et al 2018;Heidari et al 2018;Hernández-Restrepo et al 2018;Mehrabi-Koushki et al 2018;Tan et al 2018;Jayawardena et al 2019) which are listed in Table 1. The final alignment comprised 2032 characters (each gene fragment was separated with 2 "N") including gaps (ITS: 1−600, GAPDH: 603−1162 and tef1: 1165−2032).…”