Poaceascoma aquaticum Z.L. Luo & K.D. Hyde, 2016

Luo, Zong-Long, Bahkali, Ali H., Liu, Xiao-Ying, Phookamsak, Rungtiwa, Zhao, Yong-Chang, Zhou, De-Qun, Su, Hong-Yan & Hyde, Kevin D., 2016, Poaceascoma aquaticum sp. nov. (Lentitheciaceae), a new species from submerged bamboo in freshwater, Phytotaxa 253 (1), pp. 71-80 : 75-76

Poaceascoma aquaticum Z.L. Luo & K.D. Hyde , sp. nov. FIGURE 2 .

Index Fungorum: IF551351

Facesoffungi number: FoF00910

Etymology: With reference to the habitat of this taxon.

Holotype: MFLU 15−0075

Saprobic on decaying bamboo submerged in freshwater. Sexual morph: Ascomata 280−380 μm high, 310−500 μm diam, scattered, solitary, semi-immersed or erumpent through host tissue, uniloculate, globose to subglobose, glabrous, black, papilla, visible as raised, dark spots on host surface, ostiole central, with periphyses. Peridium 23−40 μm wide, of equal thickness, composed of several layers of pseudoparenchymatous cells, outer layer comprising several layers of pale black cells, arranged in a textura angularis, inner layer comprising several layers of hyaline, flattened cells, arranged in a textura prismatica. Hamathecium composed of numerous, 2−4.5 μm wide, filamentous, broad, cellular pseudoparaphyses, with distinct septa, embedded in a mucilaginous matrix. Asci 184.5–210.5 ×12–16 μm (x = 197.5 × 14 μm, n = 20), 8-spored, bitunicate, fissitunicate, cylindrical to cylindric-clavate, pedicellate, apically rounded with an ocular chamber. Ascospores 214–231 × 4.2–5.2 μm (x = 223 × 4.7 μm, n = 20), fasciculate, arranged spirally in ascus, filiform, widest at the rounded apex and tapering towards the rounded base, pale brown to brown, 21–36-septate, not constricted at the septa, smooth-walled. Asexual morph: Undetermined.

Material examined:— THAILAND. Chiang Rai Province: (N 20°3’39”, E 99°52’29”), saprobic on decaying bamboo submerged in a stream, November 2013, Z. L. Luo ZL-26 ( MFLU 15–0075 !, holotype) ; ex-type culture, MFLUCC 14-0048 , DLUCC ; ibid. ( HKAS 86450 , isotype) .

Notes:—The scolecosporous Poaceascoma species was collected from decaying culms of bamboo submerged in a freshwater stream in northern Thailand. There are many genera forming filiform ascospores in Pleosporales , such as Leptospora , Ophiobolus and Ophiosphaerella ( Shoemaker 1976, Boonmee et al. 2011, Zhang et al. 2012, Wijayawardene et al. 2014, Hyde et al. 2013, Ariyawansa et al. 2014, 2015). Phookamsak et al. (2015) introduced a new genus Poaceascoma in Lentitheciaceae , Pleosporales to accommodate the species associated with Poaceae which formed setose ascoma and filiform ascospores. Poaceascoma aquaticum resembles P. helicoides in having uni-loculate, immersed ascomata, a peridium of textura angularis to textura prismatica and filiform, multi-septate ascospores arranged spirally in the ascus. However, P. aquaticum differs from P. helicoides in having a thinner, pale black to hyaline peridium without setae, wider and longer asci (x = 197.5 × 14 μm, versus 173.5 × 9.4 μm) and ascospores (x = 223 × 4.7 μm, versus 178.1 × 2.4 μm). The phylogenetic data also confirmed them as distinct taxa ( Figure 1 ).

Figures

FIGURE 1. Phylogram generated from maximum likelihood analysis (RAxML) based on combined LSU, SSU and RPB2 sequenced data of the families in the suborder Massarineae. Bootstrap support values for maximum likelihood (ML, red) and maximum parsimony (MP, green) equal to or greater than 70% are given above the nodes. The values of the Bayesian posterior probabilities from MCMC analyses (BYPP, blue) equal or higher than 95% are given below the nodes. The tree is rooted to Melanomma pulvis-pyrius (CBS 124080). Newly generated sequences are indicated in red-gray.

FIGURE 2. Poaceascoma aquaticum (MFLU 15−0075, holotype). a, b. Ascomata on submerged wood. c. Pseudoparaphyses. d. Sections through ascomata. e. Section of peridium. f−i. Asci. j. Ascospores. k. Germinating ascospore. l. Colony on MEA. Scale bars: b = 500 μm, c = 20 μm, d, f−j = 100 μm, e = 50 μm, k = 20 μm, l = 30 mm.