Pseudosplanchnonema phorcioides (I. Miyake) Chethana, Camporesi & K.D. Hyde, 2015

Chethana, K. W. Thilini, Liu, Mei, Ariyawansa, Hiran A., Konta, Sirinapa, Wanasinghe, Dhanushka N., Zhou, Ying, Yan, Jiye, Camporesi, Erio, Bulgakov, Timur S., Chukeatirote, Ekachai, Hyde, Kevin D., Bahkali, Ali H., Liu, Jianhua & Li, Xinghong, 2015, Splanchnonema-like species in Pleosporales: introducing Pseudosplanchnonema gen. nov. in Massarinaceae, Phytotaxa 231 (2), pp. 133-144 : 139-141

Pseudosplanchnonema phorcioides (I. Miyake) Chethana, Camporesi & K.D. Hyde , comb. nov.

Basionym : Massaria phorcioides (I. Miyake) , Techn. Rep. Imper. Sericult. Exp. Stat. Tokyo 1:316 (1916).

≡ Splanchnonema phorcioides (I. Miyake) P. Leroy, L. Gauthier & M.E. Barr, Bull. Soc. mycol. Fr. 116(3): 209 (2001).

Index Fungorum number: IF550800, Facesoffunginumber: FoF: 00199; Figs. 2 , 3 .

Saprobic on dead branch of Morus sp. Sexual morph: Pseudostromata with immersed, perithecial ascomata, 159– 483 μm diam. (x=307.53 μm, n=20), solitary, gregarious, globose, black, short ostiolate. Ostiole 60–90 μm high, 80–120 μm diam. (x=78.6 × 108.6 μm, n=10), short, papillate, opening to exterior through bark. Peridium 30.5–82 μm (x=47.14 μm) wide at side walls, up to 18.9 μm wide near the apex and 60.48 μm wide at the base, comprising 6 to 7 layers of cells, outer 3–4 layers composed of dark brown, thick-walled cells of textura angularis, inner 2–3 layers comprising hyaline to pale brown, thin-walled cells. Hamathecium comprising broad, filiform 2–4 (x=3.4) μm wide, septate pseudoparaphyses, embedded in a gelatinous matrix. Asci 161–286 × 35–51 μm (x=193.2×41.9 μm, n=10), 8- spored, bitunicate, fissitunicate, cylindrical to clavate, with a short pedicel and an ocular chamber best seen in immature asci. Ascospores 50–66 × 14–20 μm (x=56.6 × 17.1 μm, n=15), overlapping biseriate, hyaline to pale brown when young, dark brown at maturity, fusiform to ellipsoidal, widest near the centre, with acute rounded ends, sometimes slightly curved, 1-sub-median septate, constricted at the septum, 5-guttulate, sometimes with pseudosepta between the guttules, smooth-walled, surrounded by a mucilaginous sheath. Asexual morph: Ceolomycetous, phoma-like. Conidiomata 382–805 μm high, 270–480 μm diam. (x=556.8 × 425.8 μm, n=10), pycnidial, solitary or aggregated, slightly erumpent, oval to globose, with verruculose wall, initially brown and becoming black at maturity. Pycnidial wall comprising multi-layered, brown, outer cells of textura angularis and thin, hyaline, inner cells. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 3.2–6.9 μm×1.5–2.5 μm (x=4.5 × 1.7 μm, n=10), enteroblastic, hyaline, smooth-walled, formed from inner layer of pycnidial wall. Conidia 3.4–8.6 μm × 1.2–3.5 μm (x=5.9 × 2.1 μm, n=40), subglobose to oblong, hyaline, aseptate, straight or occasionally slightly curved, 0–2-guttulate, smooth-walled, with rounded ends.

Cultural Characteristics:— Ascospores germinating on water agar within 24 h and the germ tubes of 3–4 μm diam. produced near the septum. Colonies slow growing on PDA, attaining 6 mm diam. after 14 days at 28 °C, edge entire, greenish black in the centre, greenish grey towards rim, white at the margin with a circular cottony mycelium on the surface and reverse black in the centre and grey towards the ends of the mycelium. Conidia in mass, white.

Material examined:— ITALY. Province of Forlì-Cesena: Modigliana, Montebello (Ibola Valley), on dead branches of Morus sp. ( Moraceae ), 13 May 2013, E. Camporesi IT-1220 tris ( MFLU 14-0929, holotype), (isotype in BBH, under the code of BBH 39847); ex-type living culture, MFLUCC 13-0533, CGMCC 3.17583; ITALY. Province of Forlì-Cesena: Santa Sofia, Camposonaldo, dead and hanging branches of Acer campestre L. ( Aceraceae ), 3 May 2013, E. Camporesi IT-1254 ( MFLU 14-0752), living culture, MFLUCC 13-0611; RUSSIA. Rostov region: Shakhty city, Central Park, on dead branch of Morus alba L. ( Moraceae ), 5 May 2014, Timur Bulgakov ( MFLU 15-0004), living culture, MFLUCC 14-0618.

Notes:— Morphologically Pseudosplanchnonema shows a resemblance to genus Splanchnonema , as typified by Splanchnonema pustulatum . Splanchnonema pustulatum differs from Pseudosplanchnonema phorcioides in possessing larger, depressed, subglobose ascomata and clavate, reddish brown, 2-septate ascospores ( Zhang et al. 2012, Liu et al. 2015). Our new collection of Pseudosplanchnonema phorcioides is identical to Splanchnonema phorcioides . Both collections have immersed, ostiolate ascomata, 8-spored, clavate, biseriate asci and fusiform, dark brown, ascospores surrounded by a gelatinous sheath ( Tanaka et al. 2005). Hence we transfer this species to Pseudosplanchnonema as a new combination. According to the molecular data, P. phorcioides clusters in a wellseparated clade in Massarinaceae . Leroy et al. (2000) has described Splanchnonema phorcioides as parasitic. Hence we have described the Pseudosplanchnonema phorcioides as also parasitic. Pseudosplanchnonema differs from M. eburnea in having smaller ascomata lacking a clypeus, a thicker peridium composed of two layers the inner of hyaline and outer of dark brown cells, anastomosing pseudoparaphyses, and larger, dark brown, 1-septate, guttulate ascospores which sometimes have pseudosepta.

Several asexual genera have been shown to be associated with Massarinaceae by molecular phylogenetic studies ( Kodsueb et al. 2007, Shearer et al. 2009, Suestrong et al. 2009, Zhang et al. 2012). Byssothecium , represented by B. circinans differs from Pseudosplanchnonema in having minute, thin-walled conidiomata and subglobose, broadly papillate pseudothecia with smaller asci and ascospores in its sexual morph ( Boise 1983). Aquaticheirospora represented by A. lignicola differs from Pseudosplanchnonema in possessing synnematous conidiomata, larger, hyaline to pale brown, cheiroid conidia ( Kodsueb et al. 2007). Cheirosporium represented by C. triseriale differs by having sporodochial conidiomata, macronematous, septate conidiophores, monoblastic, doliiform or broad-cylindrical conidiogenous cells, larger, olivaceous to brown, 0–1-septate, cheiroid conidia truncated at the base ( Cai et al. 2008, Kodsueb et al. 2007). Corynespora represented by C. olivacea , Helminthosporium represented by H. chlorophorae , H. solani , H. velutinum and Periconia represented by P. igniaria differed from the asexual morph of Pseudosplanchnonema by possessing macronematous, mononematous conidiophores, Corynespora and Helminthosporium differed by possessing brown, elongate, multi-cellular, tretic conidia, whereas Periconia differed by globose to cylindrical conidia ( Ellis 1971, Hyde et al. 2013). Neottiosporina represented by N. paspali and Saccharicola represented by S. bicolor differed from Pseudosplanchnonema in having smaller conidiomata and transversely septate conidia ( Sutton 1980).

Many studies have been conducted on splanchnonema-like species isolated from the Morus species, with distinct phylogeny and morphological characters similar to Pseudosplanchnonema ( Tanaka & Harada 2004, Tanaka et al. 2005, Liu et al. 2015). Our study shows the importance of studying these splanchnonema-like taxa since they are scattered across Pleosporales with distinct phylogenetic lineages. Therefore, further studies with molecular data are essential to interpret correct generic concepts for splanchnonema-like taxa.

Figures

FIGURE 2. Pseudosplanchnonema phorcioides (MFLUCC 13-0533). A. Pseudostroma immersed in the host tissue, B. Section of the ascoma (TS), C. Section of the peridium, D. Hyaline, pseudoparaphyses, E. Immature ascus, F–G. Mature asci, H–J. Brown ascospores, K. Ascospore with a gelatinous sheath stained in Indian ink, I. Germinating ascospore. Scale bars: A= 1 mm, B= 500 μm, C= 20 μm, D= 10 μm, E–G= 20 μm, H= 20 μm, I–L= 10 μm.

FIGURE 3. Asexual morph of Pseudosplanchnonema phorcioides (MFLUCC 13-0533). A. Conidiomata on the PDA, B. Conidiogenous cells, C. Conidia, D. Upper-view (right) and the reverse view (left) of the colony on PDA. Scale bars: A= 200 μm, B= 3 μm, C= 5 μm.