Magnibotryascoma mali

Magnibotryascoma mali Phukhams., Wanas. & K.D. Hyde, in Hyde et al., Fungal Diversity 87: 105 (2017)

Index Fungorum number: IF553255; Facesoffungi Number: FoF03387

Saprobic on dead twigs of Shorea assamica. Sexual morph: Undetermined. Asexual morph: Coelomycetous. Conidiomata 160–180 μm high, 190–210 μm diam., (x̅ = 170 × 200 μm, n = 5), pycnidial, solitary or scattered, globose to subglobose, coriaceous, uniloculate, immersed, dark brown to brown, papillate, with a central ostiole. Pycnidia wall 10–20 μm wide, thick, 2–4-layered, with outer layer composed of light brown to brown cells of textura angularis, with a hyaline innermost layer. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 4–7 × 2–3.5 μm (x̅ = 5.6 × 2.9 μm, n = 20), enteroblastic, phialidic, discrete, cylindrical to ampulliform, hyaline, arising from the inner layer of pycnidium wall. Conidia 3.6–4.5 × 2.8–3.6 μm (x̅ = 4 × 3.2 μm, n = 30), subglobose, oval, guttulate, initially hyaline, pale brown at maturity, one-celled, smooth-walled.

Culture characteristics: Conidia germinating on PDA within 24 h at room temperature (25 °C). Germ tubes produced from the basal and the apical cell of conidia. Colonies on PDA, reaching 20 mm diameter after two weeks at 20–25 ℃, mycelia superficial, velvety, circular, convex, rough surface with shiny liquid drop, entire edge, from above grayish white at the margin, sandybrown at the center, yellowish circular zonate; reverse, dark brown at the margin, pale yellowish at the center.

Material examined: China, Yunnan Province, Baoshan, on woody litter of Shorea assamica (Dipterocarpaceae), 12 July 2020, G.C. Ren, BS30 (HKAS 122711), living culture KUMCC 21-0516, KUMCC 21-0600.

Known distribution: On decaying twigs of Malus halliana (Rosaceae) (Hyde et al. 2017), on dead woody twigs of Shorea assamica (Dipterocarpaceae) in China (This study).

GenBank numbers: KUMCC 21-0516: SSU: OQ168228, LSU: OQ170877, ITS: OQ158955, tef1-α: OR613446; KUMCC 21-0600: SSU: OQ168229, LSU: OQ170878, ITS: OQ158956.

Notes: Hyde et al. (2017) introduced Magnibotryascoma mali based on the phylogenetic analyses of the combined tef1-α and rpb2 sequence data. The sexual morph is characterized by globose to subglobose conidiomata with a central ostiole, phialidic, hyaline, cylindrical conidiogenous cells, and aseptate conidia with guttules (Hyde et al. 2017). The collections were similar to M. mali (MFLUCC 17-0933) in terms of their conidial and conidiomatal characteristics (Hyde et al. 2017). Our isolates (KUMCC 21-0516 and KUMCC 21-0600) were obtained from Shorea assamica (Dipterocarpaceae) from China, respectively. Both species were collected from terrestrial habitats in Yunnan Province (China) but from different hosts. In our phylogenetic analyses of combined LSU, ITS, and tef1-α sequence data, our isolates (KUMCC 21-0516 and KUMCC 21-0600) are related to M. mali (MFLUCC 17-0933) with 89% ML bootstrap support and 1.00 BYPP value. Comparisons of the LSU and tef1-α sequence of our new isolates (KUMCC 21-0516 and KUMCC 21-0600) and M. mali (MFLUCC 17-0933) showed 100% (793/793 bp) and 100% (870/870 bp) similarity, respectively; however, ITS region shows 9.9% (29/292 bp) base pair difference. Therefore, further taxonomic work is needed to resolve identification, phylogenetic position and relationships between M. mali and other Magnibotryascoma species. Based on morphological characteristics and phylogenetic analyses, we report our collections as the first record of M. mali from decaying wood of Shorea assamica in China.

Figure 1. Phylogram generated from ML analysis based on LSU, ITS and tef1-α sequence data, representing Teichosporaceae. Related sequences are obtained following Mortimer et al. (2021) and Tennakoon et al. (2021a). Fifty-nine strains are included in the combined analyses, which comprise 2318 characters for LSU, ITS and tef1-α alignment. Two strains of Torula chromolaenae (MFLUCC 17-1514 and MFLUCC 17-1504) were used as the outgroup taxa. The best-scoring RAxML tree with a final likelihood value of -9734.934654 is presented. The matrix had 677 distinct alignment patterns, with 24.3% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.234134, C = 0.266021, G = 0.286439, T = 0.213407; substitution rates AC = 1.098317, AG = 2.075137, AT = 1.878071, CG = 1.064618, CT = 9.116965, GT = 1.0000. The tree topology of the ML analysis is similar to the Bayesian analysis. Bootstrap values for ML equal to or greater than 70% and BYPP values greater than 0.95 (the rounding of values to 2 decimal proportions) are labelled on the nodes. Strains of the newly described species are in blue, while type strains are in bold.