Sphaeropsis chromolaenicola

Sphaeropsis chromolaenicola Mapook & K.D. Hyde, in Mapook, Hyde, McKenzie, Jones, Bhat, Jeewon, Stadler, Samarakoon, Malaithong, Tanunchai, Buscot, Wubet & Purahong, Fungal Diversity 101: 113 (2020)

Index Fungorum number: IF557363

Facesofungi number: FoF 07832

Etymology: Name refects the host genus Chromolaena, on which this species was growing.

Holotype: MFLU 20-0369

Saprobic on dead stems of Chromolaena odorata. Sexual morph: Ascomata 200–235 µm high×260–285 µm diam. (x̄ =220×275 µm, n=5), immersed to erumpent through host tissue, globose, coriaceous, solitary or scattered, appearing as brown to dark brown spots. Ostiole central, short papillate. Peridium 20–50(–65) µm wide, 3–5 layers, reddish brown to dark brown cells of textura angularis. Hamathecium comprising 2.5–4 µm wide, oblong to cylindrical, septate pseudoparaphyses. Asci 90–130×34–45 µm (x̄=112×37 µm, n=10), 8-spored, bitunicate, fssitunicate, cylindric-clavate to clavate, with a short pedicel, straight to slightly curved, apically rounded with an ocular chamber. Ascospores 28.5–34×12–15 µm µm (x̄ =30×13.5 µm, n=25), 2–3-seriate, overlapping in the ascus, hyaline to yellowish brown when immature, becoming brown to dark brown at maturity, ellipsoid to ovoid, aseptate, with granular appearance, widest at the center and tapering toward narrow ends, straight to slightly curved. Asexual morph: Undetermined.

Culture characteristics: Ascospores germinating on MEA within 24 h. at room temperature and germ tubes produced from the apex. Colonies on MEA circular, mycelium velvety, moderately fufy, fliform, smoke-grey to dark olivaceous at the surface and dark in reverse.

Pre-screening for antimicrobial activity: Sphaeropsis chromolaenicola (MFLUCC 17-1499) showed no inhibition of E. coli, B. subtilis and M. plumbeus.

Material examined: THAILAND, Chiang Rai Province, Doi Pui, on dead stems of Chromolaena odorata, 2 February 2017, A. Mapook (DP98, MFLU 20-0369, holotype); ex-type culture MFLUCC 17-1499.

GenBank numbers: LSU: MT214460, ITS: MT214366, SSU: MT214412

Notes: Multigene phylogenetic analyses show that our strain Sphaeropsis chromolaenicola (MFLUCC 17-1499, ex-holotype) clusters with S. eucalypticola clade, with high bootstrap support (92% ML and 0.99 BYPP). In a BLASTn search of NCBI GenBank, the closest match of the ITS sequence for MFLUCC 17-1499 is S. eucalypticola with 100% similarity to the strain CBS 133993 (MH866075), while the closest match with the LSU sequence was with S. porosa (strain CBS 110574, DQ377895) with 99.67% similarity and closest matches with the SSU sequence were S. porosa (strain CBS 110496, NG_062740) and S. visci (strain CBS 100163, EU673177) with 99.82% similarity. Therefore, S. chromolaenicola is described as a new species based on phylogeny with morphological comparison. The new species, S. chromolaenicola is similar to S. eucalypticola in having cylindric-clavate or clavate asci with ellipsoidal to ovoid, aseptate ascospores, with wide center and tapering narrow ends, but S. chromolaenicola has wider asci (90–130×34–45 µm vs. 102−175×22–32 µm) and wider ascomata (200–235 × 260–285  µm), while S. eucalypticola has smaller ascomata in ascostromata (250–350×170−250 µm).