Murichromolaenicola thailandensis Htet, Mapook & K.D. Hyde, 2023

Htet, Zin Hnin, Tibpromma, Saowaluck, Mapook, Ausana, Chethana, K. W. Thilini & Hyde, Kevin D., 2023, Murichromolaenicola thailandensis sp. nov. (Phaeosphaeriaceae, Dothideomycetes) from Chromolaena odorata (Asteraceae) in northern Thailand, Phytotaxa 618 (2), pp. 120-132 : 126-127

Murichromolaenicola thailandensis Htet, Mapook & K.D. Hyde , sp. nov. ( Fig. 2 )

MycoBank MB 849500

Facesoffungi FOF 14609

Etymology:— Named after the country where the specimen is collected, Thailand.

Holotype:— MLFU 23-0324

Description:— Saprobic on dead stems of Chromolaena odorata . Sexual morph: Undetermined. Asexual morph: Conidiomata 130–150 × 140–160 µm (x̅ = 140 × 155 µm, n = 5), pycnidial, solitary, immersed, unilocular, globose to subglobose, black, ostiole opening through host surface, with small papillate. Peridium 15–25 µm wide, comprised of two to three layers of yellowish-brown cells arranged in textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 3–5 × 3–5 µm (x̅ =4 × 3.5 µm, n = 5), enteroblastic, phialidic, hyaline, globose to subglobose. Conidia 10–20 × 5–10 µm (x̅ =16 × 8, n = 20), yellowish brown to dark brown, oblong or oval to obovoid, round at both ends, 3–5 transverse with 1–2 longitudinal septa, not constricted at the septa, with a gelatinous cap observed clearly when mounted in Indian ink.

Culture characteristics:— Conidia germinating on PDA, reaching 25 mm diam within 7 days at room temperature, circular, entire, concentric, flat, opaque, grey on the surface; concentric, pale brown in middle and white at the margin of the reverse surface.

Material examined:— Thailand, Chiang Rai Province, Theong District, on the dead stems of Chromolaena odorata (Asteraceae) , 24 Jan. 2022, A. Mapook, TCR12 (hototype MLFU 23 -0324; ex-type culture MFLUCC 23 - 0172) .

Notes:— In the blast search of NCBI, the closest match to the ITS and tef1-α sequences of Murichromolaenicola thailandensis (MFLUCC 23-0172) is M. chromolaenae (MFLUCC 17-1489) with 99.21% (NR_168850) and 98.90% (MN998164) similarities, respectively. The closest match to the LSU sequence was Neostagonosporella sichuanensis (isolates SAUFP201604001, MH368079), with 98.86% similarity. The closest match for the SSU sequence was Parastagonospora nodurum (CBS 185.57, KY090706), with 99.71% similarity. The closest match for rpb2 was Wojnowicia italica (MFLU 14-0732, KX430004), with 90.43% similarity. In the present phylogenetic analyses, our strain clusters with M. chromolaenae (MFLUCC 17-1489) with 99% ML bootstrap support. Based on the morphological comparison, M. thailandensis resembles M. chromolaenae (MFLUCC 17-1489) by its immersed conidiomata, yellowish brown to brown cells of textura angularis and yellowish brown to brown ascospores with transverse and longitudinal septa. However, our strain differs from M. chromolaenae in having comparatively smaller conidiomata (130–150 × 140–160 µm vs 200–235 × 195–230 µm) and smaller conidia with a gelatinous cap (10–20 × 5–10 µm vs 14–25× 6.5–11 µm). Furthermore, the conidia of M. chromolaenae have ellipsoid to broadly fusiform, 5–7 transverse septa with polar appendages from both ends, while our strain has oblong or oval to obovoid conidia, rounded at both ends, 3–5 transverse septa and a gelatinous cap at one end. Moreover, M. thailandensis and M. chromolaenae differ in their culture characteristics on malt extract agar (MEA). Murichromolaenicola chromolaenae has crateriform, undulate, white cultures with greyish center at the surface and reverse colony from olivaceous center to creamy-white at the margin, while M. thailandensis has circular, entire, concentric, flat, opaque, grey at the surface and wrinkled, pale brown at the reverse surface. In addition, the nucleotide comparison of the ITS gene region of our strain and M. chromolaenae reveals 1.56% (8/512) nucleotide differences. Therefore, we introduced our strain as a new species, based on phylogeny and morphological comparison, in accordance with Chethana et al. (2021).

Figures

FIGURE 2. Murichromolaenicola thailandensis (holotype, MLFU 23-0324) a, b Appearance of conidiomata on host substrate. c Section through conidioma. d Peridium. e Conidia produced from phialidic conidiogenous cells. f–i Conidia. j–k Conidia with gelatinous cap in Indian ink. l Germinating conidium. m Culture on PDA (left: front view, right: reverse view). n Culture on MEA (left: front view, right: reverse view). Scale bars a, b = 500 µm, c = 100 µm, d = 20 µm, e = 5 µm, f–l = 10 µm.