Molecular data reveals a new holomorphic marine fungus, Halobyssothecium estuariae, and the asexual morph of Keissleriella phragmiticola

Abstract

This study introduces a novel holomorphic marine fungal species, Halobyssothecium estuariae (Lentitheciaceae, Pleosporales), from dead Phragmites communis. The new species has semiimmersed, subglobose or ellipsoidal, papillate, conical ascomata, clavate to subcylindrical, short pedicellate asci and 3-septate, fusoid to ellipsoidal ascospores with rounded ends, pale brown to dark brown central cells and hyaline end cells. The asexual morph has multiseptate, filiform, intercalary, catenate, branched chlamydospores that resemble Xylomyces. The asexual morph of Keissleriella phragmiticola based on combined LSU, SSU, ITS and TEF1 sequence analyses is reported. The role of molecular identification in delineating cryptic species are also discussed.

Phylogenetic assessment and taxonomic revision of Halobyssothecium and Lentithecium (Lentitheciaceae, Pleosporales)

“…and smaller ascospores (18-41 × 6-12 μm vs. 28-47 × 10-18 μm) (Dayarathne et al 2018). The asexual morph was not observed in the culture but Halobyssothecium species have xylomyces-like chlamydospores (Devadatha et al 2020) and phoma-like conidia (Kohlmeyer and Kohlmeyer 1979;Calado et al 2015). Keissleriella linearis E. Müll.…”

“…The taxa table was assembled based on the closest matches from the BLASTn search results and from recently published data in Dayarathne et al (2018) and Devadatha et al (2020). Sequences generated from the four markers were analyzed along with other sequences retrieved from GenBank (Table 1).…”

“…Chlamydospores apical, rarely intercalary, single or in chains, branching, filamentous, filiform to narrowly fusiform straight or curved, catenate, rarely solitary, branched, septate, with thickened septa, brown to dark brown at the septa, smooth-walled. Notes: Two species were included in Halobyssothecium, H. obiones and H. estuariae (Dayarathne et al 2018;Devadatha et al 2020), collected from various host substrates in temperate regions. In the present study, three collections of morphologically distinct isolates were encountered, two were asexual morphs (H. bambusicola and H. phragmitis) and one sexual morph (H. versicolor), which advances the current understanding of how complex the genus is.…”

“…In the present study, three collections of morphologically distinct isolates were encountered, two were asexual morphs (H. bambusicola and H. phragmitis) and one sexual morph (H. versicolor), which advances the current understanding of how complex the genus is. The complexity was noted by Devadatha et al (2020) based on previous collections by various authors. For instance, two morphologically similar taxa of H. obiones were collected but differed in ascospore measurements (24-38 × 8-14 μm vs. 38-56 × 16-22 μm) (Jones 1962;Cavaliere 1968;Webber 1970), but no sequence data was available at that time to distinguish them.…”

“…Hyde has a worldwide distribution in temperate regions and occurs as a saprobe of Agropyron junceiforme, Halimione portulacoides, Spartina species, on intertidal wood, bamboo, and exposed test panels of Betula pubescens and Fagus sylvatica (Kohlmeyer and Kohlmeyer 1979;Jones et al 2019). Devadatha et al (2020) introduced Halobyssothecium estuariae B. Devadatha, Calabon, K.D. Hyde & E.B.G.…”