Pseudoplagiostoma dipterocarpicola X. Tang, R.S. Jayaward., K.D. Hyde, & J.C. Kang, 2022

Tang, Xia, Jayawardena, Ruvishika S., Stephenson, Steven L. & Kang, Ji-Chuan, 2022, A new species Pseudoplagiostoma dipterocarpicola (Pseudoplagiostomataceae, Diaporthales) found in northern Thailand on members of the Dipterocarpaceae, Phytotaxa 543 (4), pp. 233-243 : 238-240

Pseudoplagiostoma dipterocarpicola X. Tang, R.S. Jayaward., K.D. Hyde, & J.C. Kang , sp. nov.

Index Fungorum number: IF559459; Facesoffungi number: FoF10497; FIGURE 2 .

Etymology: The epithet refers to the genus of the host plant, Dipterocarpus .

Holotype: MFLU 21-0177

Associated with the twigs and fruits of Dipterocarpus sp. Sexual morph: Undetermined. Asexual morph: Associated with the twigs of Dipterocarpus sp. , coelomycetous. Conidiomata 63–153 μm long × 113–288 μm diam. (x̅ = 109 μm × 203 μm, n = 25) immersed in the twigs of the host, medium brown to dark brown, pycnidia with pale yellow cylindrical strips of exuding conidia, subglobose, subcuticular to epidermal, unilocular, and irregularly breaking through plant tissue at the centre. Conidiomata wall 6–23 μm wide, thin-walled, composed of 2–5 dark brown layers, thickest near the base of the conidiomata, pseudoparenchymatous cells textura angularis, intermixed with the host cells at the base and on the sides. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 5.0–11 μm × 1.0–2.5 μm (x̅ = 9 × 2.0 μm, n = 25), proliferating enteroblastically, appearing as phialides with thickenings and collarette or with a percurrent proliferation in the apical portion, discrete, arising from the inner cell layer, hyaline, smooth, ranging from cylindrical with a long, slimy cylindrical neck to ampulliform, straight and short when wider at the base. Conidia 9.0–22 μm × 4.0–7.5 μm (x̅ = 16 × 6 μm, n = 35), hyaline, ellipsoidal to elongated ellipsoidal, guttulate, smooth, thickwalled (0.5–1.5 μm), aseptate, apex broadly obtuse, straight or lightly curved at the base, with a prominent hilum or the hilum absent, frequently slightly narrow at the middle, the base tapering to a flat protruding scar.

Culture characteristics: Colonies developing on PDA are incubated at room temperature and reach a diameter of 30 mm after 15 days, flat, spreading, with a fluffy, moderately mouse-gray mycelium. Surface lightly rough with pale gray hyphae, colonies somewhat sunken in the middle, and with an irregular edge. The reverse side dark brown but pale brown at the margins, lobate at the center and not pigmented.

Material examined: Thailand, Chiang Mai Province, Mushroom Research Center, on dead twigs of Dipterocarpus sp. , 08 August 2019, Xia Tang, Dip 31 (holotype: MFLU 21-0177; ex-type living culture: MFLUCC 21-0142), on dead fruits of Dipterocarpus sp. , 08 August 2019, Xia Tang, Dip 16 (paratype: MFLU 21-0260; ex- paratype living culture: MFLUCC 21-0114) .

Notes: Pseudoplagiostoma dipterocarpicola forms a clade with P. mangiferae with highly support (78% ML, 68% MP and 1 BYPP), but P. dipterocarpicola can be easily distinguished from P. mangiferae . Pseudoplagiostoma dipterocarpicola has dark brown, conidiomata with a thick wall at the base, two types of conidiogenous cells, these ranging from cylindrical with a long, slimy cylindrical neck to ampulliform and wider at the base, straight, short and without paraphyses, whereas P. mangiferae has a yellowish brown conidiomata wall, cylindrical to ampulliform conidiomata that are wider at the base, straight conidiogenous cells and paraphyses ( Cheewangkoon et al. 2010). Based on pairwise nucleotide comparisons, P. dipterocarpicola is different from P. mangiferae in 31/620 bp (3%) in ITS, 7/814 (0.98%) in LSU, 63/410 bp (15%) in tef1-α and 87/450 (19%) in tub2. Based on the combination of morphological characters and multigene phylogeny, we describe P. dipterocarpicola herein as a distinct species according to the guidelines of Jeewon and Hyde (2016).

Figures

FIGURE 2. Pseudoplagiostoma dipterocarpicola (MFLU 21-0177, Holotype). a Conidiomata immerse on the twigs of host. b Specimen with conidiomata. c Section of conidiomata. d Peridium. e–g Conidiogenous cells. h–k Conidia. l Germinated conidium. m, n Colony on PDA (up-front, down-reverse). Scale bars: b = 500 μm, c = 50 μm, d = 20 μm, e–g = 10 μm. h–l = 5 μm.