Huntiella hellenica F.F. Liu. Marinc. & M.J. Wingf., 2020

Liu, FeiFei, Marincowitz, Seonju, Chen, ShuaiFei, Mbenoun, Michael, Tsopelas, Panaghiotis, Soulioti, Nikoleta & Wingfield, Michael J., 2020, Novel species of Huntiella from naturally-occurring forest trees in Greece and South Africa, MycoKeys 69, pp. 33-52 : 33

Huntiella hellenica F.F. Liu. Marinc. & M.J. Wingf. sp. nov. Fig. 2

Etymology.

The name refers to the country, Greece where this fungus was collected.

Mating strategy.

Homothallic, with sexually complementary isolates having both the MAT1-1-1 and MAT1-2-1 genes.

Sexual state. Ascomata produced in 2% MEA in a week, perithecial; ascomatal bases mostly embedded in thick or loose mycelial mat, globose to ellipsoidal or obpyriform, pale brown when young, becoming dark brown with age, 173-377 µm long (avg. 238.8 µm), 157-493 µm wide (avg. 218.2 µm), ornamented with spine-like structures, dark brown, conical, 12-29 µm long, 4-9 µm wide at base becoming attenuated; ostiolar necks upright, straight, occasionally situated at off-centre of base, darker than base when young, 344-616 µm long (avg. 515.5 µm), 34-60 µm wide (avg. 46.6 µm) at base, gradually tapering towards apex; ostiolar hyphae hyaline, straight to divergent, 15-39 µm long, 1-3 µm wide, tapering towards apex. Asci evanescent. Ascospores hyaline, subglobose, aseptate, covered with sheath giving a hat-like feature in side view, 4-5.5 × 3-4.5 µm (5 ± 0.23 × 4 ± 0.28 µm) excluding sheath.

Asexual state. Thielaviopsis -like Conidiophores macronematous, simple or branched; when branched radiating from basal cell once, often reduced to conidiogenous cells . Conidiogenus cells endoblastic, hyaline, varying from lageniform to cylindrical depending spore shape; in case of thick barrel-shaped conidia, apex often becoming wider than base. Conidia hyaline, 1-celled, in two recognisable shapes; majority ellipsoidal to barrel-shaped (side swollen, ends round), typical fat barrel-shaped 5-8 × 4.5-7.5 µm (5.9 ± 0.61 × 5.3 ± 0.55 µm), width of some barrel-shaped ranging 2.5-4 µm wide; rectangular-shaped (side straight, ends truncated), not commonly found, 5-9 × 1-3 µm (6.9 ± 1.18 × 2.3 ± 0.38 µm). Aleurioconidia not observed.

Culture characteristics.

Cultures on 2% MEA in dark in 8 d showing circular growth with even edge, mycelium flat, superficial, medium dense and texture becoming pelt-like with age, colour above not uniform, salmon (11 f’) to ochreous (15 b’) with inner half irregularly umber (13m), below ochreous (15 b’) with inner half irregularly umber (13 i’) at centre. Optimum growth temperatures at 30 °C at 9.6 mm/d, followed by at 25 °C (7.6 mm/d), 35 °C (7.2 mm/d), 20 °C (4.7 mm/d), 15 °C (3.2 mm/d), 10 °C (1.1 mm/d) and 5 °C (0.2 mm/d).

Specimens examined.

Greece, Phthiotis, near the village Kastri, occurring on freshly-cut stumps of Platanus orientalis in a natural forest along the banks of the Spercheios River, Nov. 2018, P. Tsopelas & N. Soulioti, PREM 62889, holotype (dried culture of CMW 54800), culture ex-holotype CMW 54800 = PPRI 27982, other cultures CMW 54801 = PPRI 27983.

Notes.

The sexual state of H. hellenica developed at temperatures over 25 °C. Cultures incubated at 20 °C and below produced only the asexual state. Huntiella hellenica is closely related to H. savannae ( Kamgan Nkuekam et al. 2008), H. pycnanthi ( Mbenoun et al. 2016) and H. krugeri . It can, however, be distinguished from these two species by the dimensions of ascomatal necks and barrel-shaped conidia and growth rate. Huntiella hellenica produced shorter (average 515.5 μm long) ascomatal necks than H. savannae (average 579 μm long) and H. pycnanthi (average 673 μm long). Huntiella hellenica had larger (average 6.9 × 2.3 μm) barrel-shaped conidia than H. savannae (average 4.8 × 3 μm) and H. pycnanthi (average 6 × 3 μm). Optimal temperature for growth of H. hellenica was 30 °C, similar to H. savannae and H. pycnanthi , but H. hellenica differed from H. pycnanthi in growing minimally at 10 °C and below.

Figures

Figure 2. Micrographs of Huntiella hellenica sp. nov. (ex-holotype CMW 54800 = PPRI 27982) A culture grown on 2 % MEA at 30 ° C (optimum growth temperature) in the dark for 34 d B, C colony with ascomatal base embedded in mycelia with ascospore mass at the tip of ostiolar neck D-F young ascoma showing development of ostiolar neck and less-pigmented base G, H mature ascoma ornamented with spines I close-up of ascomatal wall showing spines J-L close up of ornament (spin-like) M, N Ostiolar hyphae O Ascospores P Ascospores covered with sheath appearing like a hat Q, R Germinating ascospores S Lageniform conidiogenous cell T Cylindrical-shape conidiogenous cell U Conidia in various shapes from diverse barrel-shaped to rectangular-shaped V rectangular-shaped conidia W chains of conidia. Scale bars: 1 mm (B, C); 50 µm (D-H); 10 µm (I-W).