Neobelonopsis cinnabarina Itagaki & Hosoya, 2023

Itagaki, Hiyori & Hosoya, Tsuyoshi, 2023, A new genus Neobelonopsis and two new species of Trichobelonium (Helotiales, Ascomycota) discovered mainly from poaceous grasses native to Asia in Japan, MycoKeys 99, pp. 45-85 : 45

Neobelonopsis cinnabarina Itagaki & Hosoya sp. nov.

Figs 5 , 13 , 14C

Etymology.

Cinnabarina in Latin, referring to the remarkable color of disc.

Diagnosis.

Differs from all other Neobelonopsis species by reddish orange disc.

Holotype.

TNS-F-86682, Yuzawa Town, Minami-uonuma County, Niigata Pref., Japan, 31 October 2021, on decaying culms of Miscanthus sinensis , ex-holotype culture NBRC 115571.

Description.

Apothecia developed from scuta. Scuta superficial, scattered to gregarious, flat discoid, pale reddish brown (C30-60M80Y80-100K10) to dark brown (C40-60M80Y100K60), 125-375 µm diam., textura epidermoidea. Apothecia flat to cushion-shape, 0.2-0.5 mm high, with blackish brown (C100M100Y80-100K60) to greenish dark brown (C80M80Y80-100K60) receptacle, releasing magenta pigment (C40-20M100Y10-30K60) in 3% KOH; disc 0.6-2 mm diam., light orange (C0-30M80Y100K0) to reddish orange (C0-20M100Y100) when fresh, shrunk to 0.3-1.5 mm diam. Ectal excipulum 25-40 µm thick at base, 15-25 µm thick at the upper flask to margin; cortical cells clavate to pyriform, 14-18(-20) × 8.5-10 µm at base, becoming smaller toward the margin, 10-12 × 5-7 µm, containing yellow to orange cytoplasm which turns magenta in 3% KOH, containing guttules that disappeared in 3% KOH. Medullary excipulum 25-50 µm thick. Asci (56-)62-75(-83) × 6-7.5 µm, arising from croziers, with MLZ + apical pore. Ascospores 15-20(-22.5) × 3.5-4.5 µm, ellipsoid to subcylindrical, with rounded to subacute extremes, aseptate, hyaline or yellow when mounted fresh in water, containing 2(-4) large guttules. Paraphyses (50-)60-75(-80) × 2.5-3.5 µm, wider toward the apex up to 5 µm, simple, septum distance closer towards the base, containing long yellowish refractive vacuoles when mounted fresh in water, changed magenta in 3% KOH and showing color gradation (darker toward the tip). Subiculum thinly developed the surface of substrate, sparse to moderately abundant around the scuta and apothecia, shiny brown; subicular hyphae straight to curved, sometimes forming fascicules with 2-3 hyphae, 2.5-4 µm diam. with 0.5-1 µm thick-walls, branched at right angle, walls covered by a thick gelatinous substance. Colony of NBRC 115571 on PDA entire to slightly undulate, flat to slightly winkled, floccose to felted, brownish gray (C0-20M30-40Y40K30) from the surface, turning white at the edge, same color from the reverse, without soluble pigment; crystals ovoid to dumbbell-shape, 18-25 × 11-15 µm, hyaline, forming on surface or below agar; aerial mycelium sparse to dense, gray. Conidiophores semi-macronematous, solitary to caespitose (forming rather loose sporodochia), short, constricted, arising vertically or laterally from hyphae, pale to dark brown, smooth, thick-walled, branched; phialides round-bottom flask or bottle-shape, up to 20 µm long, 3-4 µm width at base, discrete to integrated, terminal or intercalary, pale brown, thick-walled, with cylindrical collarettes of 8-10 × 2 µm; conidia aseptate, cylindrical oblong to fusiform, abundantly aggregated in slimy heads, 4-5 × 1 µm, hyaline, thin-walled.

Additional specimens examined.

TNS-F-86690 and 86692, Yuzawa Town, Minami-uonuma County, Niigata Pref., 31 October 2021, on decaying culms of Miscanthus sinensis ; TNS-F-86701, Daigenta Lake, Yuzawa Town, Minami-uonuma County, Niigata Pref., 31 October 2021, on decaying culms of M. sinensis , culture NBRC 115669; TNS-F-86704 and 86716 (culture NBRC 115670), Toukamachi City, Niigata Pref., 31 October 2021, on decaying culms of M. sinensis .

Notes.

Neobelonopsis cinnabarina is easily distinguished from other species by the reddish orange disc, slightly clavate paraphyses, and strong magenta pigment release of apothecia in KOH. In particular, the brilliant color of disc of this fungus is a rare feature in mollisioid fungi, except for Mollisia purpurea Rhem and M. russea (Schmid-Heckel) Baral. These two species share several characters with N. cinnabarina , such as dark scuta [ N. russea has "dunkelbraunen Schild" sensu Schmid-Heckel (1988)], bright orange vacuoles in paraphyses that become intensely magenta (red violet) in KOH, ocher to brown receptacle, asci arising from croziers, aseptate ascospores, and monocot host (Rhem 1907; Schmid-Heckel 1988; Baral and Marson 2005; Richter and Baral 2008). As the tips of fresh paraphyses turn dark magenta in 3% KOH (Fig. 5M ), this phenomenon is suggested to be a vital reaction as the pigments diffuse uniformly in the paraphyses after heat drying. Richter and Baral (2008) also described the same reaction in M. russea . These features imply a close relationship among N. cinnabarina , M. purpurea , and M. russea . However, M. russea has no subiculum, ascospores are shorter (11-16 × 2.5-3.5 µm) than N. cinnabarina , and paraphyses are not clavate. Mollisia purpurea also differs from N. cinnabarina in having crystals in medullary excipulum and shorter ascospores (12-14 × 2.5-3 µm) than N. cinnabarina . Genetic comparison among these species could not be conducted as M. purpurea and M. russea lack available DNA sequences.

Neobelonopsis cinnabarina produces conidiophores only on CMA (Fig. 5S ), and conidia mostly germinate (Fig. 5U ). The asexual stage of N. cinnabarina is unique in loose sporodochia (Fig. 5V ), longer collarettes, and oblong conidia (Figs 5U-X , 14C ).

Figures

Figure 5. Neobelonopsis cinnabarina (TNS-F- 86682, holotype) A fresh apothecia on the decaying culm of Miscanthus sinensis B immature apothecium protruding from the stroma C dried apothecia D one month old colony on PDA E texture of stroma (in LA) F vertical section of the apothecium (in LA) G yellowish reflective vacuoles in fresh paraphyses (in water) H yellowish vacuoles in outermost cells of fresh ectal excipulum (in water) I immature ascus with yellowish cytoplasm (in water) J ascospores with yellowish cytoplasm (in water) K apothecium that dissolved magenta pigments when immersed in 3 % KOH L outermost cells that turned magenta (in 3 % KOH) M fresh paraphyses that turned magenta, note that the tips have a darker color (in 3 % KOH) N ascospores (in CB / LA) O asci with ascospores (in CB / LA) P paraphyses with wide, blunt head (in CB / LA) Q blue-stained apical pore of ascus (in Melzer's solution after 3 % KOH pretreatment) R crozier at the base of ascus (in CB / LA); S collapse conidiophores with slimy conidial drops on CMA (arrows) T hyphae with oblong-shape crystals on CMA U conidia (in water) V clusters of conidiophores (in water) W, X discrete conidiophores (in water). Scale bars: 1 mm (A, S); 0.1 mm (B); 0.5 mm (C); 50 μm (F-H, M, T, V); 20 μm (E); 10 μm (I, J, L, N-R, U, W, X).

Figure 13. Line-drawings of the Neobelonopsis and Trichobelonium species I vertical section of the apothecium showing the marginal structure of ectal excipulum, medullary excipulum, and hymenium II asci III paraphyses IV ascospores. Scale bars: 10 μm.

Figure 14. Asexual morph and hyphal structures of the Neobelonopsis and Trichobelonium species A conidiophores of N. acutata B monilioid hyphae of N. bicolor C conidiophores with conidia of N. cinnabarina D conidiophores with conidia of N. didymospora E conidiophores with conidia of N. microspora F conidiophores with conidia of N. multiguttata G conidiophores with conidia of N. obtusa H conidiophores with conidia of T. albobarbatum I hyphal mass with melanized appressorium-like structure of T. miscanthi. Scale bars: 10 μm.