Pseudobambusicola thailandica Hern.-Restr. & Crous

Rupcic, Zeljka, Chepkirui, Clara, Hernandez-Restrepo, Margarita, Crous, Pedro W., Luangsa-ard, Janet Jennifer & Stadler, Marc, 2018, New nematicidal and antimicrobial secondary metabolites from a new species in the new genus, Pseudobambusicolathailandica, MycoKeys 33, pp. 1-23 : 8-9

Pseudobambusicola thailandica Hern.-Restr. & Crous sp. nov.

Etymology.

The epithet refers to Thailand, where this species was collected.

Type.

THAILAND. Lop Buri Province: Chai Badan, Wang Kan Lueang Arboretum, Wang Kan Lueang Waterfall, on twig (unidentified), 14 Jul 2015, M. Hernández-Restrepo, MHR 1534 (holotype: BBH 42022!, culture ex-type BCC 79462!).

Description of fungal structures on SNA.

Mycelium composed by hyaline to pale brown, septate, smooth to slightly verruculose, hyphae, 1-2.5 µm wide. Conidiomata pycnidial, semi- or entirely immersed in the agar, solitary or aggregated, erumpent, globose, sometimes with a neck, opening via central ostiole, dark brown, 63-360 µm diam., sometimes with a cylindrical neck 50-125 × 40-50 µm, opening via central ostiole; at the base of the conidiomata are often present globose to subglobose cells, thick-walled, 5-9 µm wide; conidiomata surrounded by dark brown, smooth to slightly verruculose hyphae, 2-2.5 µm wide. Conidiophores reduced to conidiogenous cells. Conidiogenous cells phialidic with periclinal thickening, subcylindrical to ampulliform, hyaline, smooth, 6.5-7 × 2.5-4 µm. Conidia exposed in white, mucous drops at the ostiole of pycnidia, composed by macro- and microconidia. Macroconidia produced in white, mucous heads, solitary, fusoid-ellipsoid, apex bluntly to subobtusely rounded, tapering to a distinctly truncate base, mostly straight, but sometimes slightly curved, prominently guttulate, hyaline, smooth, 0-3-septate, 10-20 × 2 –4(– 6) µm. Microconidia produced in the same pycnidia with macroconidia, solitary, oblong to cuneiform, non-guttulate to slightly guttulate, hyaline, smooth, aseptate, 2 –4(– 5.5) × 1-2 µm, apex rounded, base truncate. Chlamydospores brown, terminal, in chains, 16-38 × 5-6 µm. Sexual morph not observed.

Culture characteristics.

Colonies on OA at 25 °C reaching 24 mm diam. in 2 weeks, elevated, with dense cottony mycelium at the centre, mouse grey, margin whitish, effuse to fimbriate; reverse dark mouse grey.

Notes.

Pseudobambusicola is introduced here for a pycnidial coelomycete producing two kinds of conidia. Morphologically, it is similar to the species of Bambusicola and Neobambusicola . However, asexual morphs in Bambusicola are characterised by brown or pale brown conidia and annellidic rather than phialidic conidiogenous cells and hyaline conidia as in Pseudobambusicola ( Dai et al. 2012, 2017). Neobambusicola is a monotypic genus erected for N. strelitziae , first described from South Africa growing on necrotic leaf tissue associated with Phyllachora strelitziae ( Phyllachoraceae , Phyllachorales , Sordariomycetes) ( Crous et al. 2014). Both genera are similar in having pycnidial conidiomata and phialidic conidiogenous cells that produce fusoid-ellipsoid macro- and subcylindrical microconidia. However, in the new genus, the conidiomata are surrounded by dark brown, smooth to slightly verruculose hyphae and, in mature conidiomata, a cylindrical neck is often present; furthermore, chlamydospores can be present in culture. Although both genera belong to the Sulcatisporaceae ( Pleosporales , Dothideomycetes), they are placed in different clades, Neobambusicola is more closely related to Sulcatispora (100 %, 1 pp), while Pseudobambusicola was placed in a distinct branch with Magnicamarisporium (Fig. 1). Additionally, based on LSU, ITS and tef1 sequences, P. thailandica is 97 % (KP004495) and 83 % (KP004467) and 93 % similar to N. strelitziae , respectively.