Mariannaea humicola L. Lombard & Crous

Gajanayake, Achala J., Jayawardena, Ruvishika S. & Luangharn, Thatsanee, 2023, Revealing new records of hypocrealean fungicolous fungi from northern Thailand, Phytotaxa 630 (3), pp. 211-228 : 221-224

Mariannaea humicola L. Lombard & Crous , in Lombard, van der Merwe, Groenewald & Crous, Stud. Mycol. 80: 213 (2015) Fig 4

Index Fungorum number: IF810165, Facesoffungi Number: FoF 14744

Fungicolous on the fruiting bodies of Marasmius sp. Sexual morph: not observed. Asexual morph: on the host, Mycelium present as scattered white cottony masses. On PDA, hyphomycetous, Hyphae 3–6 μm (x = 4 μm, n = 30) wide, septate, hyaline. Conidiophores 100–310 × 2–5 μm (x = 204.5 × 3.5 μm, n = 20), rising from aerial hyphae or the agar surface, verticillately branching at 2–3 levels, with a terminal whorl of 1–6 phialides, and forming 1–2 lower nodes with 1–3 phialides or rarely with single phialides. Phialides 11–23 × 2–4 μm (x = 15.5 × 3 μm, n = 40), subulate, with a slightly swollen base, having an inconspicuous collarette. Conidia 3.5–7 × 2–4 μm (x = 5 × 3 μm, n = 45), produced in chains and later separated to be single, fusiform to ellipsoidal to obovoid, hyaline, some are slightly guttulate, with a hilum at both or at one end. Chlamydospores intercalary or terminal.

Colony characters:—on PDA, at 25 °C, reached 50–60 mm after 7 days of incubation. Having a velutinous appearance, with age turning funiculose to fasciculate, slightly powdery nature due to sporulation, initially the surface of the colony pale yellowish, later with age turning brown to dark brown, margin regular irregular.

Material examined:— Thailand, Chiang Mai Province, Mae Tang, Pa Pae, Ban Pha Deng, isolated with the mycelium growing on a cap of Marasmius sp. , 6 July 2021, Gajanayake A.J, MR 07 (inactive dry culture MFLU 23- 0422), living culture MFLUCC 23-0205.

GenBank accession numbers:—MFLUCC 23-0205: ITS: OR473193; LSU: OR473255; tub2: OR742383; tef1α: OR742382.

Notes:—In the phylogenetic analyses, our isolate MFLUCC 23-0205 clustered with Mariannaea humicola strains CBS 740.95 and CBS 102628 with 99 % BS and 0.86 PP value. Additionally, the morphological characteristics of our isolate MFLUCC 23-0205, described herein, are similar to the original description and illustrations given in Lombard et al. (2015). The conidiophore length and the phialides length of MFLUCC 23-0205 are higher than those of M. humicola , described by Lombard et al. (2015): conidiophores: 100–310 × 2–5 μm vs. 80–100 × 3–7 μm, phialides: 11–23 × 2–4 μm vs. 10–20 × 2–4 μm. In contrast to M. humicola described in Lombard et al. (2015), chlamydospores and conidial chains were observed in MFLUCC 23-0205. These differences may have occurred due to the variations of the agar medium, the conditions used to obtain the cultures, and the time spent observing the morphology after isolation. Therefore, we confirmed that our isolate MFLUCC 23-0205 is M. humicola . There are previous reports of M. humicola being isolated from soil and the seagrass Posidonia oceanica as an epiphyte ( Lombard et al. 2015, Le 2019, Botta et al. 2020). To the best of our knowledge, this is the first report of M. humicola on a fruiting body of Marasmius sp. as a fungicolous fungus from Thailand.

Figures

FIGURE 4. Mariannaea humicola (MFLU 23-0422). a Host (Marasmius sp.) b Mycelium presents as scattered white cottony masses on the host (marked in black arrows). c, d Colony on PDA. e Sporulation on PDA. f–k Conidiophores with verticillate phialides. l, m Chlamydospores. n Conidia. Scale bars: c, d = 30 mm, e = 100 μm, f–k = 50 μm, l, m = 10 μm, n = 5 μm.