Mrakia arctica M. Tsuji emend. R.R. Jia & F.L. Hui

Zhang, Kai-Hong, Shi, Cheng-Feng, Chai, Chun-Yue & Hui, Feng-Li, 2020, Mrakia panshiensis sp. nov. a new member of the Cystofilobasidiales from soil in China, and description of the teleomorphic-stage of M. arctica, MycoKeys 74, pp. 75-90 : 75

Mrakia arctica M. Tsuji emend. R.R. Jia & F.L. Hui

Description.

The yeast Mrakia arctica was described as an asexual species ( Tsuji et al. 2018). Among soil yeasts isolated in the present study, strain NYNU 18469 collected from Liaoning provinces, formed hyphae and teliospores on CM agar (Fig. 3 ). In spite of the observation of sexual behavior in that species, the description of Mrakia arctica M. Tsuji, Mycoscience 59 (1): 57. 2018 (MB 821502) is emended below.

True hyphae with terminally and intercalarily teliospores are developed after 2 months at 10 °C on CM agar (Fig. 3A ). Culture NYNU 18469 demonstrated similar morphological characteristics with those of the previously reported yeast-stage morphs, except for the yeast-forming teliospores. Teliospores are spherical, 6-12 µm in diameter, single and in short chains of 2-4 spores. Teliospores germinate by a bud-like projection (Fig. 3B, C, D ). Physiologically, both asexual and sexual morphs of M. arctica were identical, except for a few reactions on standard growth. The asexual morph of M. arctica can assimilate l-sorbose and grows in the presence of 0.01% cycloheximide, and grows at 20 °C, but not for the sexual morph.

Deposits.

culture NYNU 18469 was isolated from the soil of the Tianhuashan National Forest Park, Liaoning Province, China, in September 2018. It is preserved in a metabolically inactive state at Microbiology Lab, Nanyang Normal University, Henan, China. Ex-type cultures are deposited at the China Centre of Industrial Culture Collection (CICC), Beijing, China, as CICC 33354, and at the CBS Yeast Collection of the Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands, as CBS 10867.

Figures

Figure 3. The teliospore-stage morph of Mrakia arctica (NYNU 18469) A. True hyphae with teliospores terminally and intercalary; B / C / D. Teliospores produced with a bud-like projection. Scale bars: 10 μm.