Cytospora heveae Senwanna, Cheew. & K.D. Hyde, in Senwanna et al. Mycosphere 12(1), 1402 (2021).
Index Fungorum number: IF559362, MycoBank number: MB559362, Facesoffungi number: FoF16091
Saprobic on Microcos paniculata woody litter. Sexual morph: Stromata solitary, immersed, and uni- or multi-loculate. Ascomata 105–253 μm high, 150–280 μm wide (x̅= 179 × 214 μm, n = 5), perithecial, immersed or semi-immersed in a stroma, erumpent, scattered, mostly subglobose, glabrous, brown to dark brown, with ostiolar neck. Peridium 14–26(–30) μm wide, composed of two layers, a brown outer layer and a sub-hyaline inner region, the outer layer comprising compact thick-walled cells of textura angularis, inner layer comprising thin-walled cells of textura angularis to textura prismatica. Paraphyses 3.2–6(–6.9) μm wide (x̅= 4.5 μm, n = 20), cylindrical, hyaline, septate, moderately constricted at septa. Asci (17.4–)19–29 × 3.4–6.3(–6.8) μm (x̅= 24.6 × 4.7 μm, n = 25), 8-spored, unitunicate, sessile, clavate to elongate obovoid, apically truncate, with a J- apical ring. Ascospores (5.5–)6–8(–8.5) × 1.7–2.6 μm (x̅= 7.2 × 2.2 μm, n = 35), biseriate, overlapping, elongateallantoid, straight to slightly curved, aseptate, hyaline to light yellow, smooth-walled. Asexual morph: Undetermined.
Culture characteristics – Ascospore germinated on PDA within 24 h and germ tubes emerged from one or both sides. Colonies on PDA reached 8 cm diam. after 7 days at room temperature (25– 28 °C), circular, medium dense, umbonate elevation, upper surface white becoming whitish cream with age, reverse buff becoming brown with age.
Material examined – Thailand, Chiang Rai Province, Doi Tung National Park, on dead wood of Microcos paniculata (Malvaceae), 09 September 2022, N. Afshari, 3C3T1R8 (MFLU 24-0410); living culture MFLUCC 24-0537.
GenBank numbers – act = PX753037, ITS = PQ800242, LSU = PV072598, rpb2 = PV138149, tef1-α = PV138147.
Known hosts – Hevea brasiliensis (Senwanna et al. 2021), Microcos paniculata (this study).
Known distribution – Thailand (Senwanna et al. 2021, this study).
Notes – The asexual morph of C. heveae (MFLU 21-0203) identified as a coelomycete, was isolated from canker on a seedling stem of Hevea brasiliensis (Euphorbiaceae), in Thailand by Senwanna et al. (2021). The morphology could not be compared since we reported its sexual morph. However, morphological characters of our collection are congruent to the sexual morphs of other Cytospora species in having immersed to erumpent, solitary ascostromata, ellipsoid to clavate, J-apical ring asci, and aseptate, hyaline, and ellipsoid to allantoid ascospores (Shang et al. 2020, Monkai et al. 2021b, Senwanna et al. 2021, Wang et al. 2024b). In the phylogeny, our isolate 4879 (MFLUCC 24-0537) clustered together with C. heveae (MFLUCC 17-0358) with high support (100% ML, 0.99 PP). There is not a significant sequence difference among these isolates. Therefore, based on the guidelines of Jeewon & Hyde (2016), we consider the new collection (MFLU 24-0410) to be a new host record and new record of the sexual morph of C. heveae.
Figure 1 – Cytospora heveae (MFLU 24-0410, a new host record and first report of the sexual morph). a Close-up of ascomata on Microcos paniculata woody litter. b Longitudinal section of the ascomata. c Vertical section through ascomata. d Section of peridium. e Asci and paraphyses. f–i Asci. j–n Ascospores. o Germinated ascospores. p Colonies on PDA (front and reverse). Scale bars: a, b = 500 μm, c = 100 μm, e = 20 μm, d, f–j, o = 10 μm, k–n = 5 μm.