Poaceascoma koreanum H. Liu & H. Sang 2025, sp. nov.

Poaceascoma koreanum H. Liu & H. Sang sp. nov. Fig. 24 Etymology. Name refers to Korea, the country from where it was isolated. Description. Poaceascoma koreanum differs from its closest phylogenetic neighbour P. lochii (BRIP 71546) by unique fixed alleles in two loci: ITS positions 13 (A), 16 (C), 19 (G), 20 (T), 21 (C), 22 (G), 28 (G), 29 (indels), 41 (C), 42 (C), 44 (C), 45 (T), 46 (C), 47 (G), 50 (T), 51 (T), 52 (C), 58 (G), 60 (C), 68 (C), 84 (T), 98 (C), 107 (indel), 109 (C), 112 (indels), 114 (G), 116 (C), 124 (G), 125 (A), 127 (C), 130 (C), 131 (T), 132 (C), 136 (A), 137 (G), 140 (T), 141 (T), 144 (A), 153 (indel), 155 (G), 156 (T), 157 (A), 158 (C), 165 (C), 166 (G), 168 (A), 176 (A), 350 (indels), 388 (C), 391 (T), 397 (G), 404 (T), 410 (A), 420 (C), 435 (C), 440 (C), 443 (G), 447 (C), 449 (G), 450 (A), 469 (T), 475 (G), 476 (T), 481 (T), 489 (T), 495 (A), 497 (G), 500 (A), 502 (C); LSU positions 100 (G), 104 (indel), 138 (C), 141 (G), 143 (G), 145 (G), 205 (C), 206 (C), 210 (C), 488 (C), 550 (T), 700 (C), 705 (C), 755 (G), 907 (T). Culture characteristics. Colony reaching 39.72 mm diam. on PDA after 7 days in darkness at 25 ° C, front side greyish-yellow, reverse side black-brown, margins burr-like (Fig. 24 a). Type. South Korea • South Jeolla Province, Hwasun, isolated from roots of Zoysia japonica, October 2020, H. Liu and H. Sang, holotype CMML 20-44 H (permanently preserved in a metabolically inactive state), ex-holotype CMML 20-44, ex-isotype CMML 20-45; CMML 20-46. Notes. No conidiogenous structures or sexual morph were observed in strains CMML 20-44, CMML 20-45 and CMML 20-46. On MEA, chlamydospore-like structures (4.5–10.5 μm in width) in hyphae were observed after incubation for two weeks (Fig. 24 b – g). In multi-loci phylogeny, based on ITS, LSU, SSU and TEF 1, these three strains formed a distinct single clade within the genus Poaceascoma sister to clade comprising strain of P. magnum (ex-type CMML 20-47 and ex-isotype CMML 20-71), P. herbaceum (ex-type GZCC 19-0046), P. helicoides (ex-type MFLUCC 11-0136 and representative strain MFLU 11-0172) and P. lochii (ex-type BRIP 71546) (Fig. 26). Based on nucleotide sequence comparison, P. koreanum (CMML 20-44) differed from ex-type strain of P. lochii (BRIP 71546) in two loci: ITS identities = 456 / 518 (88.03 %), 40 gaps; LSU identities = 882 / 896 (98.44 %). P. koreanum (CMML 20-44) differed from ex-type strain of P. helicoides (MFLUCC 11-0136) in four loci: ITS identities = 381 / 428 (89.02 %), 41 gaps; SSU identities = 915 / 916 (99.89 %); LSU identities = 779 / 793 (98.23 %); TEF 1 identities = 896 / 958 (93.53 %). Compared to ex-type of P. herbaceum (GZCC 19-0046), nucleotide sequences were different in these loci: ITS identities = 335 / 380 (88.16 %), 41 gaps; SSU identities = 1021 / 1025 (99.61 %); LSU identities = 890 / 904 (98.45 %); TEF 1 identities = 897 / 958 (93.63 %). P. koreanum (CMML 20-44) also differed from ex-holotype strain of P. magnum (CMML 20-47): ITS identities = 433 / 500 (89.02 %), 45 gaps; SSU identities = 1028 / 1032 (99.61 %); LSU identities = 884 / 900 (98.22 %); TEF 1 identities = 874 / 924 (94.59 %). All of these species were originally found on herbaceous plants. Specifically, P. lochii was found on leaves of turf-grass Zoysia matrella, P. helicoides and P. herbaceum were saprophytes on dead stem of Digitaria sanguinalis and dead culm of unidentified herbaceous plants, respectively (Phookamsak et al. 2015; Hyde et al. 2017; Tan et al. 2021). Morphologically, P. herbaceum, P. helicoides and P. lochii were described, based on their sexual morph, while only chlamydospore-like structures were observed in strains CMML 20-44, CMML 20-45 and CMML 20-46. Additionally, P. magnum differs from these strains in producing large chlamydospores. Therefore, Poaceascoma koreanum sp. nov. was introduced in this study.