Diatrypella macrospora Mehrabi, R. Hemmati, L.N. Vasilyeva & F.P. Trouillas, 2016

Mehrabi, Mehdi, Hemmati, Roghayeh, Vasilyeva, Larissa N. & Trouillas, Florent P., 2016, Diatrypella macrospora sp. nov. and new records of diatrypaceous fungi from Iran, Phytotaxa 252 (1), pp. 43-55 : 47-48

Diatrypella macrospora Mehrabi, R. Hemmati, L.N. Vasilyeva & F.P. Trouillas sp. nov. ( Fig. 2 )

MycoBank MB 813001, Facesoffungi number: FoF 01891

Differs from other Diatrypella species by the size of ascospores (12–20 × 1.7–3 μm).

Etymology:—Refers to the rather large ascospores.

Type:— IRAN, Kohkiluyeh & Buyer Ahmad Province, Sisakht City, on dead branches of Quercus brantii Lindl. ( Fagaceae ), 9 April 2014, M. Mehrabi, KDQ15 ( IRAN 16679 F, Holotype), ex-type living cultures, IRAN 2344 C.

Saprobic on oak branch. Sexual morph: Stromata immersed in the bark of dead branches (2 cm diameter), 1.5–2.5 mm diam, discrete, erumpent, circular, surface black, delimited by a black zone in the host tissues, with groups of 3–10 perithecia, white to yellow to light brown entostroma, Perithecia 400–700 μm diam, usually not compressed, hyaline to black (with age), circinately arranged, monostichous, shining inside, globoid. Necks of the perithecia about 200–500 μm above the periderm, converge together, black. Ostioles black, opening separately. Asci elongate, sporiferous parts 110–150 (–160) × 10–15 μm, basal part filiform, up to 80 mm long, narrow when young and more or less cylindrical when mature, with obtuse apex, poly spore. Ascospores (10–) 12–20 (–23) × 1.7–3 (–3.7) μm (av.=15.8 × 2.3 μm, n=39), allantoid, subhyaline, yellowish in mass, thinwalled, smooth, aseptate, usually with two oil droplets. Paraphyses elongate, filiform, septate.

Asexual morph: immersed in bark, acervuli interspersed amongst stromata, rare, 0.5–1 mm diam, flat to subconical, hymenium labyrinthiform, yellow, with yellow stratum of spores. Conidia slender and strongly arcuate, 20–40(–44) × 0.6–0.8 μm.

Cultural characteristics:—Colonies circular to slightly irregular, cottony with moderately dense, fluffy aerial mycelium, white on PDA, reverse primrose (23 ,, b), covering 75 mm Petri-dish after 2 weeks at 24° C.

Notes:— A literature review on Diatrypella (e.g., Saccardo 1882, Ellis & Everharts 1892, Berlese 1900, Chacon 2003, Vasilyeva & Stephenson 2005, Trouillas et al. 2011) highlighted the unique features of this taxon. Diatrypella macrospora can easily be distinguished from other species of the genus by its large ascospores (12–20 μm). Diatrypella macrospora is similar to D. persica Rick. in respect to ascospore size. However the latter has wider ascospores (14–17 × 4 μm vs. 12–20 × 1.7–3 μm, Saccardo 1913). The new species also differs in having prominent perithecial necks emerging in groups. Phylogenetic analysis indicates that the new species belongs to Diatrypella and is closely related to D. quercina and D. iranensis (bootstrap value = 82% in MP and 95% in NJ, Fig. 1 ). Morphologically, the new species can easily be distinguished by having larger ascospores (6–7× 1–1.3 μm in D. iranensis and 8–12 × 2–3 μm in D. quercina, Mehrabi et al. 2015 , Croxall 1950). The new species also differs by its longer necks.

Figures

FIGURE 1. One of the 48 most parsimonious trees obtained from the ITS sequence data. MP/NJ Bootstrap support values from 1000 replicates higher than 50% are reported at the nodes.The original strain numbers are noted after the species names. The ex-type strains are in bold. The new sequences obtained in this study are indicated in highlight.

FIGURE 2. Diatrypella macrospora from Quercus brantii, (1) Habit of ascostromata on bark. (inset: close-up of perithecia necks in lateral view), (2) Longitudinal section through the stroma shows ostioles and perithecia (3,4) Anamorph (5) Ascus with ascocpores (6) Ascospores (7) Conidia (8) Colony morphology on PDA.—Bars 1 = 1 mm. 2,3,4 = 500 μm. 5,6,7= 20 μm.