Fusarium celtidicola Q.J. Shang, E. Camporesi & K.D. Hyde, 2018

Shang, Qiu-Ju, Phookamsak, Rungtiwa, Camporesi, Erio, Khan, Sehroon, Lumyong, Saisamorn & Hyde, Kevin D., 2018, The holomorph of Fusarium celtidicola sp. nov. from Celtis australis, Phytotaxa 361 (3), pp. 251-265 : 255-259

Fusarium celtidicola Q.J. Shang, E. Camporesi & K.D. Hyde , sp. nov. Figs 2–3

Index Fungorum number: IF 553845; Facesoffungi number: FoF 02453

Etymology:—Names reflect to the host, of which the holotype was collected from “Celtis-inhabiting”.

Saprobic on dead wood of Celtis australis Linn. Sexual morph Ascomata 75–215 μm high × 70–210 μm diam. (x = 147 × 143 μm, n = 7), superficial, solitary to gregarious, blue-black to dark purple, subglobose to ampulliform,

or obpyriform, like dried persimmons or collapsing laterally when dry. Ostioles blue-black to dark purple, with periphyses. Peridium 30–40 μm wide, composed of two layers, inner 3–5 layers, comprising of hyaline cells of textura angularis to textura prismatica, outer 3–5 layers, comprising brown to dark purple, thick-walled cells of textura angularis. Hamathecium comprising hyaline, distinctly septate catenophyses, each cell 12.7–17.5 μm long × 14.2– 22.5 μm wide. Asci (70–)90–100(–109) × (7–)9–13(–16) μm (x = 89 × 11, n = 40), 8-spored, unitunicate, clavate,

with short pedicel, with slightly rounded to truncate at the apex. Ascospores (8–)16–20(–25) × (4.5–)6–7.5(–9) μm (x = 18 × 6.6, n = 165), overlapping 1–2-seriate, hyaline, varied in shape, ellipsoidal to oblong, or subglobose to obovoid, or fusiform, with both ends rounded, 0–3-septate, constricted at the septa, smooth-walled. Asexual morph Hyphomycetous. Chlamydospores ellipsoidal to pyriform, single or chain inter the hyphae. Conidiophores bicellately branched, septate, hyaline, cylindrical, smooth. Conidiogenous cells (11.5–)13.5–28(–37) × (1.5–)2.5–4 μm (x = 21 × 3.2, n = 20), monophialidic, subulate, ampulliform to sub-cylindrical, some proliferating percurrently, straight or curved, apically distorted on conidial secession. Macroconidia (31–)34–40(–43) × (4–)4–4.8(–5.3) μm (x = 36.5 × 4.5, n = 55), hyaline, naviculate to falcate, beak at the base, 3–5-septate. When conidia formed, the chlamydospores normally single inter the hyphae and the mycelium not swollen ( Fig.3 a ). Microconidia (16–)17–20(–23) × (2.5–)2.5– 3(–3.2) μm (x = 18.7 × 2.9, n = 115) hyaline, oblong to naviculate, straight or curved, with a rounded apex, a truncate base or beak at two sides of the cell, 1–3-septate. Normally the conidia forming when the chlamydospores with the chains inter the hyphae and most of the mycelium with swelling ( Fig. 3 b ).

Culture characteristics:—Colonies on MEA from above and below reddish, pigmentation uniform or variegated. Aerial mycelium on PDA white to yellowish or vinaceous. Ascospores germinating on PDA within 48 h. Germ tubes produced from any cell. Colonies on PDA reaching 2.5–4 mm diam. after 7 d in the dark at 16 °C, edge crenate, flat or effuse. After 7 d colonies white above, reddish at the center, in reverse reddish-white.

Material examined:— ITALY, Forlì-Cesena Province, Forlì, Viale dell’ Appennino, on dead branch of Celtis australis ( Ulmaceae ), 19 November 2015, E. Camporesi, IT 2691 ( MFLU 15-3646, holotype!; HKAS 95020, isotype!), ex-type living culture, MFLUCC 16-0526, KUMCC 16-0019.

Notes: —Based on phylogenetic analyses and morphological comparison, our isolate belongs to the genus Fusarium . Phylogenetic analyses of a combined RPB 1 and RPB 2 sequence data ( Fig. 1 ) show that Fusarium celtidicola ( MFLUCC 16-0526) clusters in the Fusarium citricola species complex ( FCCSC). Fusarium celtidicola forms a distinct lineage, sister to F. citricola Guarnaccia, Sandoval-Denis & Crous ( CPC 27805, CPC 27709, CPC 27069, CPC 27067, CPC 27813) and F. salinense Sandoval-Denis, Guarnaccia & Polizzi ( CPC 26403, CPC 26457, CPC 26973) with high support values (100% ML, 100% MP and 1.00 PP). Moreover, F. celtidicola differs from F. citricola and F. salinense in its conidial characters and host occurrence (see Table 2). Fusarium celtidis Ellis & Tracy , a Celtis-inhabiting fungus which has been found on the same host with F. celtidicola , lacks a detailed description or molecular data ( Index Fungorum 2018, NCBI 2018). However, the species differs from F. celtidicola based on the size of macroconidia [ F. celtidis , 40–60 × 4–5 μm versus (31–)34–40(–43) × (4–)4–4.8(–5.3) μm, F. celtidicola ] ( Ellis & Tracy 1890).

Figures

FIGURE 1. Maximum likelihood majority rule consensus tree of analysis of species in Fusarium generated from a combined dataset of RPB1 and RPB2 sequence data. Bootstrap support values for maximum likelihood (red) and maximum parsimony (black) equal or greater than 70% are shown above the nodes. The Bayesian posterior probabilities values (green) greater than 0.95 are also indicated above the nodes. The new isolates are in blue, ex-type strains are in bold. The tree is rooted to Nectria cinnaburina (CBS 125165)

FIGURE 2. Fusarium celtidicola (MFLU 15-3646, holotype!) a Appearance of ascomata on the host surface. b Vertical section of ascoma. c Ostiole with periphyses. d Peridium. e Catenophyses. f–h Asci (h = in Melzer’s reagent). i–n Ascospores. o Germinating ascospore. p, q Culture on PDA (p = colony from above, q = colony from below). Scale bars: a = 100 μm, b = 30 μm, d, i–n = 10 μm, e = 20 μm, f–h, o = 15 μm.

FIGURE 3. Asexual morph of Fusarium celtidicola produced on PDA. a, b Mycelium growing on PDA. c–e Conidiogenous cells with conidia. f Conidiogenous cell. g–j Chlamydospores. k Conidia. l–o Macroconidia. p–t Microconidia. Scale bars: a, b, k = 20 μm, c–i, l–t= 10 μm.