Mariannaea imbricata D. Hirose & K. Watanabe, 2021

Watanabe, Kohei & Hirose, Dai, 2021, A novel Mariannaea species isolated from decayed pine needles in Japan, Phytotaxa 522 (3), pp. 211-220 : 217-218

Mariannaea imbricata D. Hirose & K. Watanabe sp. nov. ( Figure 3 )

MycoBank no.: 840111

Description:

Sexual morph not observed. Colony diam., 7 d, in mm (average): PDA: 5˚C (2), 10˚C (8), 15˚C (11), 20˚C (26), 25˚C (31), 30˚C (31), and 35˚C (no growth); MEA: 25˚C (34). Colonies on PDA at 25˚C, matted felt at center, indistinctly zonate, with undulate margins, irregularly oriented and coarsely undulated, producing radially oriented fan-shaped structures from the center to margin, amber with white margin and reverse sienna with white margin. Colonies on MEA at 25 °C, matted felt at center, indistinctly zonate, with undulate margins, irregularly oriented and coarsely undulate, producing radially oriented fan-shaped structures from center to margin, white with ochreous margin, and reverse umber with fulvous margin. On PDA: hyphae 1.4‒6.3 µm wide, hyaline, smooth, thin-walled, branched and septate. Conidiophores 167.7‒798.4 µm (mean 451.0 µm, n = 50) long, 3.7‒8.5 µm (mean 6.1 µm, n = 50) wide at the basal cell, generally macronematous, mononematous, erect, septate, smooth thin-walled, hyaline, bearing short branches with 1–2 whorls of 2–5 phialides, or phialides formed in verticils on long main stalk. Phialides 6.2‒16.9 × 1.2‒2.4 (mean 10.4 × 1.7 µm, L/ W 6.2, n = 50), typically slender flask-shaped, hyaline and smooth-walled. Conidia 4.7‒10.9 × 1.8‒3.2 µm (mean 6.2 × 2.5 µm, L/ W 2.5, n = 50), generally fusiform to ellipsoidal, hyaline, smooth and thin-walled, aseptate and produced in imbricate chains. Chlamydospores 7.2‒22.2 × 4.6‒12.3 µm (mean 10.8 × 6.2 µm, L/ W 1.7, n = 50), intercalary or terminal, produced singly or in short chains, globose to sub-globose, hyaline and thick-walled.

Etymology:

The epithet “imbricata” refers to the irregularly oriented and coarsely undulate morphology from the center to margins of colonies grown on PDA and MEA.

Type : Sugadaira, Nagano, Japan, 2008, isolated from the decayed needles of Pinus densiflora (Holotype, TNS-F- 91410, dried culture on PDA; ex-type culture, NBRC 33105 ) .

Notes:

Mariannaea imbricata is morphologically similar to M. atlantica , M. fusiformis , M. punicea , and M. terricola , but can be distinguished from these congeners by its slender flask-shaped phialides with a smooth-walled texture. The colonies are characterized by an amber to white pigmentation on PDA and a central matted felt texture, and with the center to margins irregularly oriented and coarsely undulate on PDA and MEA. This species does not form reddish-purple colonies. Phylogenetic analysis based on ITS and TUB-2 sequences can also be used to distinguish these species.

Figures

FIGURE 3. Morphology of Mariannaea imbricata sp. nov. A‒H. Culture characteristics on potato dextrose agar (PDA) and malt extract agar (MEA). The upper and lower rows of plates show colonial growth after 7 (A, B, E, F) and 14 days (C, D, G, H), respectively. From left to right, the upper and basal surfaces of colonies grown on PDA (A‒D) and MEA (E‒H) are placed in sequential order. I. A scanning electron micrograph of the surface of conidia. J‒N. Microstructure after 7 days of incubation on PDA under a differential interference contrast microscope. J, conidia. K, imbricate conidial chains. L, phialides, and M and N, intercalary or terminal chlamydospores. Scale bars indicate 10 µm.