Discovery of a new species of the Hypoxylon rubiginosum complex from Iran and antagonistic activities of Hypoxylon spp. against the Ash Dieback pathogen, Hymenoscyphus fraxineus, in dual culture
Pourmoghaddam, Mohammad Javad
Lambert, Christopher
Surup, Frank
Khodaparast, Seyed Akbar
Krisai-Greilhuber, Irmgard
Voglmayr, Hermann
Stadler, Marc
MycoKeys
2020
66
105
133
69BA22CB-5B18-534E-91A0-A4637BC8E989
GUM 1588
GUM
1588
Sordariomycetes
Xylariaceae
Hypoxylon
CoL
Fungi
Hypoxylon rubiginosum subsp. sp.
Xylariales
0
105
Ascomycota
species
rubiginosum
Teleomorph. Stromata superficial, pulvinate, up to 1 cm long x0.2-0.5 cm wide, with inconspicuous to conspicuous perithecial mounds; surface Orange (7) to Apricot (42); Orange (7) granules beneath the surface and Laeden Black (126) granules between the perithecia, with Orange (7) KOH-extractable pigments. Perithecia obovoid to compressed-obovoid, 0.35-0.65 high x0.3-0.45 mm wide. Ostioles umbilicate, inconspicuous. Asci with amyloid, discoid apical apparatus, 1-1.5 µmhigh x2-3 µmwide, stipe up to 160 µmand spore-bearing portion 70-100 x6-8 µmlong. Ascospores smooth, unicellular, brown to dark brown, ellipsoid, inequilateral with narrowly-rounded ends, 10-15 x5-6.5 µm, with straight to slightly sigmoid germ slit spore-length on convex side; perispore dehiscent in 10% KOH; epispore smooth.
Cultures and anamorph. Colonies on OA covering a 9 cm Petri dish in 3 wk, at first white, becoming whitish, cottony, azonate with entire margins; remaining mainly uncoloured with Pale Luteous tinges. Anamorph not produced in culture.
Specimen examined. Iran, Mazandaran Province, Tonekabon County, Do-hezar forest, 36°42'30"N, 50°49'43"E, 456 m elev., on dead branches (host unknown), 28 Oct 2016, M.J. Pourmoghaddam (GUM 1588; culture MUCL 57725).
Notes. This specimen is morphologically similar to Hypoxylon aff. rubiginosumGUM 1587, but it can be distinguished by its larger ascospores [10-15 x5-6.5 vs. 8-10 (-11) x(3-) 4-4.5 (-5) μm]. H. rubiginosum sensu strictodiffers from this specimen in having smaller ascospores [(8-) 9-12 x4-5.5 vs. 10-15 x5-6.5 μm]. In addition, the stromatal secondary metabolite profile is similar to that of H. rubiginosumwith two unknown azaphilone compounds of the mitorubrin / rubiginosin family ( UC 2, retention time = 8.7 min, 442 Dalton and UC 3, RT = 10.6 min, 884 Da) and rubiginosin A. H. guilanensediffers from Hypoxylon aff. rubiginosumGUM 1588 in having stromata with hemispherical to pulvinate shape and difference in average ascospores sizes (12-15 x5-6 vs. 10-15 x5-6.5 μm) with straight germ slit. H. texensediffers from Hypoxylon aff. rubiginosumGUM 1588 in having Rust (39) to Dark Brick (86) KOH-extractable pigments and much smaller ascospores [9.1-10.8 (-11.5) x(4.0-) 4.5-5.4 (-5.7) vs. 10-15 x5-6.5 μm]. Figure 6. Hypoxylon aff. rubiginosum(GUM 1588) Astromatal habit Bclose-up view of stromatal surface, with stromatal pigments in 10% KOH Csection of stroma showing perithecia and ostioles Dascus in Melzer'sreagent Eascospores in 10% KOH with dehiscent perispore. Scale bars: 2.5 mm ( A); 0.5 mm ( B, C); 20 µm( D); 10 µm( E).