Microdochium sichuanense L.S. Dissan., J.C. Kang & Maharachch., 2023

Dissanayake, Lakmali S., Kang, Ji-Chuan & Maharachchikumbura, Sajeewa S. N., 2023, Microdochium sichuanense sp. nov. (Microdochiaceae, Xylariales), from a Poaceae host in Sichuan, China, Phytotaxa 600 (3), pp. 206-216 : 211-212

Microdochium sichuanense L.S. Dissan., J.C. Kang & Maharachch. , sp. nov. (FIGUER 2)

Index Fungorum Number: IF900348, Facesoffungi: 14277

Etymology:— Referring to the location “ Sichuan Province ” where the fungus was collected Holotype:—KUN-HKAS127240

Saprobic on dead leaves of Poaceae in terrestrial habitats. Sexual morph: Ascomata 100–180 μm high, 60–100 μm diam. (x̅ = 146.3 × 86.9 μm, n = 5), solitary, scattered, appear as black dots on the host surface, square to ellipsoidal, brown, immersed, apapillate, ostiolate. Peridium 10–20 μm wide, evenly thickened, comprising brown cells of textura angularis to textura prismatica, flattened and hyaline towards inner layers, fused with host tissues. Hamathecium comprising hyaline, cylindrical, guttulate, branched paraphyses (2–6 μm wide), arising from base of ascomata. Asci 90–140 × 15–20 μm (x̅ = 110 × 18 μm, n = 15), unitunicate, 8-spored, overlapping 1–2 seriate, clavate to oblong, with a minute J- apical ring or without an epical ring, with a short stipe. Ascospores 10–22 × 4–7 μm (x̅ = 16 × 5.5 μm, n = 15), hyaline, oval to fusiform, sometimes allantoid, straight or slightly curved, guttulate. Asexual morph: Undetermined

Culture characteristics:— Colonies on PDA reaching 2 cm diam. after 2 weeks at 20–25 °C, medium dense, circular to slightly irregular, slightly raised, cottony surface smooth, at first white, becoming light yellow when mature, without any pigmentation; reverse yellowish-white.

Material examined:— China, Sichuan Province, Chengdu, University of Electronic Science and Technology premises, on dead leaves of an unidentified poaceous host, September 2021, Q Wang W30 ( KUN-HKAS127240 , holotype), ex-type cultures KUNCC 23–13008

Known distribution:— Sichuan Province, China

Notes:— Microdochium sichuanense morphologically resembles M. graminearum and M. shilinense in having solitary, scattered, immersed, apapillate, ostiolate ascomata, textura angularis to prismatica cells in peridium, 8- spored, biseriate with short stipe asci, and hyaline, guttulate, fusiform, straight or curved ascospores. Microdochium sichuanense differs from M. graminearum and M. shilinense in having clavate to oblong asci without an apical ring and aseptate ascospores, while M. graminearum and M. shilinense have fusiform asci with apical ring and 0–3 transversely septate ascospores. Multi-gene phylogenetic analyses ( FIGURE 1 ) show that our collection forms a sister group with the isolates of M. hainanense (SAUCC210781 and SAUCC210782) with 60% ML and 0.96 BYPP. It is impossible to compare M. sichuanense and M.hainanense as they occur in different morphs (sexual and asexual).A pairwise nucleotide comparison between the two species showed that M. sichuanense differs from M. hainanense (SAUCC210782) in 35/566 bp of ITS (6.18%) and 150/797 bp of rpb2 (18.82%). Interestingly, both species were collected from the same host family ( Poaceae ), but from different locations in China ( M. sichuanense : Sichuan Province and M. hainanense : Hainan Province).

Figures

FIGURE 1. RAxML tree based on a combined dataset of analyzed LSU, ITS and rpb2 sequences. Bootstrap support values for ML equal to or greater than 60%, Bayesian posterior probabilities (BYPP) equal to or greater than 0.95 are shown as ML/ BYPP above the nodes. The new isolate is in blue; ex-type strains are in bold. The scale bar represents the expected number of nucleotide substitutions per site.