Bipolaris chusqueae Madrid, Cantillo & R. Castillo, sp. nov. (Fig. 4)
MycoBank number: MB 551452; Index Fungorum Identifier: IF 551452; Facesoffungi number: FoF 10417;
Etymology: The name refers to the bamboo genus Chusquea, from which this fungus was isolated.
Holotype: SGO 166370
Vegetative hyphae septate, branched, light olivaceous to mid brown, thin- to thick-walled, smooth to verruculose, 1.5–7 µm wide, occasionally showing deposits of a mucilaginous dark brown material. Sexual morph: Undetermined. Asexual morph: Conidiophores macronematous, mononematous, mostly solitary, but sometimes caespitose, septate, simple, straight to flexuous, more or less geniculate at the fertile portion, light olivaceous brown to dark brown, often paler at the apex, smooth to verruculose with cell walls often thicker than those of the supporting vegetative hyphae, 31–350 × 5–8 µm with subnodulose to nodulose intercalary swellings up to 10 µm wide. Conidiogenous cells integrated, terminal and intercalary, mostly subcylindrical, mono- to polytretic, proliferating sympodially, 12–30 µm long. Conidia subcylindrical to narrowly clavate, straight to slightly curved, light olivaceous brown to dark brown, smooth, (17–)26–50(–68) × 10–12(–15) µm, 2–9(mostly 3)-distoseptate, with a rounded apex and an obconically truncate or rounded base. Hilum thick and dark with a conspicuous central germ pore.
Material examined: CHILE, Marga Marga Province, La Campana National Park, isolated from Chusquea cumingii, 30 June 2015, H. Madrid (SGO 166370, holotype), ex-type living culture HM 240.
Notes: This taxon was commonly isolated from stems and roots of an endemic Chilean bamboo species, Chusquea cumingii. BLAST searches of ITS sequence from the ex-type strain, HM 240 revealed that Bipolaris chusqueae is closely related to B. cynodontis CBS 109894 (ex-type strain, GenBank KJ909767, 99.30% similarity), B. axonopicola BRIP 11740 (ex-type strain, GenBank KX452443, 99.30% similarity), B. austrostipae BRIP 12490 (ex-type strain, GenBank KX452442, 99.15% similarity) and B. coffeana CBS 126976 (ex-type strain, GenBank MH864366, 99.15% similarity). In BLAST searches with the GPDH sequence of HM240, the closest matches were B. austrostipae BRIP 12490 (GenBank KX452408, 98.62% similarity) and B. cynodontis CBS 285.51 (GenBank LT715772, 97.80% similarity). Conidia of Bipolaris cynodontis, 27–100 × 10–20 μm (Manamgoda et al. 2014), are larger than those of B. chusqueae. However, the conidia of B. axonopicola, B. austrostipae and B. coffeana are similar sizes and are more easily distinguished by the number of distosepta, i.e. 5–10, 6–9, and (4–)6(–7), respectively (Manamgoda et al. 2014, Tan et al. 2016). In addition, none of these species have been reported from species of Chusquea.
Figure 4 – Bipolaris chusqueae (SGO 166370, holotype). a. Conidiophore. b, c. Conidia and conidia attach to conidiogenous cells. d-i. Conidia. j. Verruculose hyphae. Scale bars: a-c = 30 µm, d-g = 25 µm, h, i = 10 µm.