Melanographium smilacis Boonmee, Huanraluek & K.D. Hyde, sp. nov.

Index Fungorum number: IF 558546; MycoBank number: MB 558546; Facesoffungi number: FoF 09964; Fig. 1

Etymology – The specific epithet “smilacis” reflects the host genus Smilax.

Holotype – MLFU 21-0075

Saprobic on dead stems of Smilax perfoliate. Sexual morph Undetermined. Asexual morph Colonies on natural substrate superficial, effuse, velvety, tufted, dark brown. Mycelium immersed, composed of branched, septate, smooth, brown hyphae. Conidiophores 270–561×2–7 μm (x̅=460×5 μm, n=20), macronematous, loosely or densely, fascicle, panicle or tufted, unbranched, multi-septate, straight below, slightly flexuous, geniculate near the apex, brown to dark brown below, brown to pale brown towards the apex, subhyaline at the tip, thick-walled, rarely with percurrent proliferations. Conidiogenous cells polyblastic, integrated, terminal, sympodial, cylindrical or slightly clavate, with minutely protruding conidiogenous scars. Conidia 11–17×4–13 μm (x̅=14×9 μm, n=50), holoblastic, acropleurogenous, solitary, reniform or broad obovoid to semicircular, slightly curved, olivaceous brown to dark brown, aseptate, large guttulate when immature, verrucose or smooth-walled. Conidial secession schizolytic.

Culture characteristics – Conidia germinated on MEA, colony circular and flat, reaching 3.5 cm in 2 weeks at 25 °C, dense, effuse, velvety, radially with fimbriate edge, white grey to pale brown in surface, reddish brown to brown in reverse, with orangish yellow pigmented in media, with radiating outwards mycelium with dull white margin.

Material examined – THAILAND, Chiang Rai, Muang, Doi Lan, on dead stems of Smilax perfoliate L. (Smilacaceae), 27 March 2019, S. Boonmee, DL1 (MFLU 21-0075, holotype), ex-type living culture, MFLUCC 21-0098.

GenBank numbers – ITS=MZ538514, LSU=MZ538548, SSU=MZ538572, TEF1-α=MZ567091.

Notes – Melanographium smilacis was found on dead stems of Smilax perfoliate (Smilacaceae). Melanographium smilacis shares common characters with species in Melanographium such as effused and tufted colonies, loosely or densely fascicle and brown conidiophores and reniform shape, aseptate with dark pigmented conidia (Saccardo 1913; Trotter 1931; Ellis 1963, 1971; Goh and Hyde 1997; Somrithipol and Jones 2005; Hyde et al. 2020b). Phylogenetically, Melanographium smilacis is as a sister lineage with the ex-type strain of M. phoenicis (MFLUCC 18-1481) with 100% MLBS, 1.00 BYPP support (Fig. 2). However, M. smilacis differs from M. phoenicis and other species in terms of the conidial features such as reniform or broad obovoid to semicircular shapes and lacking a slit (Fig. 1). According to the morphological and phylogenetic analyses, we introduce a new species, Melanographium smilacis.

Figure 1 – Melanographium smilacis (MFLU 21-0075, holotype). a, b Appearance of colonies on natural substrate. c, d Squash mount of conidiophores with attached conidia. e, f Close-up of conidiophores showing septation with paler at the apex. g, h Apex of conidiophores with developing conidia. i–l Conidia with a basal scar. m Germinated conidium. n, o Culture on MEA from surface and reverse. Scale bars: b=100 µm, c, d=200 µm, e–h=50 µm, i–l=5 µm, m=10 µm

Figure 2 – Maximum likelihood phylogenetic tree based on a combined LSU and ITS sequence data of Melanographium taxa and related genera. The tree is rooted with Fasciatispora calami (MFLUCC 15-0294) and F. cocoes (MFLUCC 18-1445). Bootstrap support values for maximum likelihood (MLBS, left) equal to or greater than 70% is given above the nodes. Bayesian posterior probabilities (BYPP, right) equal to or greater than 0.95 are given above the nodes. Ex-type strains are in bold and newly generated sequence is in blue