Capnodiales » Dissoconiaceae » Dissoconium

Dissoconium eucalypti

Dissoconium eucalypti Crous & Carnegie, in Crous et al., Fungal Divers 26(1): 157 (2007)

Index Fungorum number: IF501103; Facesofungi number: FoF 06961

Holotype: AUSTRALIA, New South Wales, Morpeth Park, Plantation, Bonalbo, 152º 36′ 47″ E, 28º 46′ 3″, on leaves of Eucalyptus tereticornis, 8 February 2006, A. Carnegie, CBS-H 19770, cultures ex-type CPC 13004 = CBS 120039, CPC 13005–13006.

Associated with dead branches of Laurus nobilis. Appearing as black raised, spots, each surrounded by a thin, yellow border. Sexual morph: Ascomata up to 180–315 µm high, 240–340 µm wide, pseudothecial, single, globose, immersed becoming erumpent, dark brown, ostiolate. Ostiole 63–90 µm high, papillate, periphysate. Peridium 22–36 µm wide, composed of 3–4 layers of thick-walled, medium brown cells of textura angularis, with yellow vacuoles, inner layer of fattened, hyaline cells of textura angularis. Pseudoparaphyses lacking. Asci 90–105 × 15–28 µm (x̄ = 96 × 19.8 μm, n = 15), 8-spored, bitunicate, fasciculate, subsessile, cylindrical-clavate to broadly clavate, straight or slightly incurved. Ascospores 16.3–28.8 × 7.1– 10.6 µm ( x̄ = 24.3 × 8.6 μm, n = 35), bi-seriate above, uni-seriate below, filling the ascus almost completely, ellipsoid-fusoid, with subobtuse ends, 1-septate, equilateral or inequilateral, constricted at the septum, with 2 larger guttules and many small guttules, straight to slightly curved, hyaline, with a mucoid sheath. Asexual morph: See Crous et al. (2007).

Material examined: ITALY, Province of Forlì-Cesena, Via Lombardini - Forlì, dead aerial branch of Laurus nobilis (Lauraceae), 24 November 2016, E. Camporesi, IT3170 (MFLU 162906).

Known host and distribution: Eucalyptus tereticornis (Australia), Malus domestica (United States) (Farr and Rossman 2020).                     

GenBank Numbers: ITS: MN699134; LSU: MN699129

Note: Our new collection groups with ex-type strain of Dissoconium eucalypti (CBS 120039) which was isolated from Eucalyptus tereticornis in Australia (Crous et al. 2007), with high statistical support (96% ML, 1.00 BYPP). However, there were no sexual morphs have been reported for D. eucalypti or Dissoconium (Crous et al. 2007). Our new fungus resembles Dissoconiaceae in having pseudothecial, immersed, globose, unilocular, papillate ascomata and ellipsoid-fusoid, 1-septate, hyaline ascospores (Crous et al. 2009). DNA sequences of D. eucalypti strains (MFLU 16–2906 and CBS 120039) differ in 2 nucleotides of the ITS region (0.4%, no gaps), while LSU sequences were identical. However, molecular data does not provide evidence for delimiting the new collection from D. eucalypti (Jeewon and Hyde 2016). Hence, it is reported here as the sexual morph of D. eucalypti.

 

Figure x. Dissoconium eucalypti (MFLU 162906). a Herbarium material. bc Appearance of ascomata on host substrate. d Section through ascoma. e Section through the peridium. f Section through ostiole. g–j Asci. k–p Ascospores. (n–p in 5% KOH). Scale bars: c = 500 µm, d = 200 µm, e–j = 50 µm, k–p = 20 µm.

 

References:

 

Crous PW, Summerell BA, Carnegie AJ, Mohammed C et al. 2007 – Foliicolous Mycosphaerella spp. and their anamorphs on Corymbia and Eucalyptus. Fungal Diversity 26, 143–185.

Crous PW, Schoch CL, Hyde KD, Wood AR et al. 2009 – Phylogenetic lineages in the Capnodiales. Studies in Mycology 64, 17–47.

Farr DF, Rossman AY 2020 – Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. http://nt.ars-grin.gov/fungaldatabases/

Hyde KD, Dong Y, Phookamsak R, Jeewon R et al. 2020 – Fungal diversity notes 1151–1276: taxonomic and phylogenetic contributions on genera and species of fungal taxa. Fungal Diversity 16:1–273.

Jeewon R, Hyde KD 2016 – Establishing species boundaries and new taxa among fungi: recommendations to resolve taxonomic ambiguities. Mycosphere 7, 1669–77.

 

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