Colletotrichum sambucicola Jayaward., Camporesi & K.D. Hyde, in Tibpromma et al., Fungal Diversity 83: 131 (2017)
Index Fungorum number: IF 552553; Facesofungi number: FoF 2683
Holotype: MFLU 16-2675
Saprobic on a dead branch of Sambucus ebulus L. Sexual morph: Undetermined. Asexual morph: Conidiomata 0.13–0.4 mm (x̄ = 0.27 mm, n = 10) diam., black, acervulus, oval, solitary, gregarious. Setae straight or ± bent, abundant, dark brown, becoming paler towards the apex, opaque, smooth-walled, septate, 1–6-septate, 110–145 μm long, base cylindrical, slightly inflated, 6.1–8.5 μm diam., apex acute to rounded, smooth. Conidiophores simple, to 20 lm long, hyaline to pale brown, smooth-walled. Conidiogenous cells 9–16 × 2–4 μm (x̄ = 11.9 × 2.9 μm, n = 20), phialidic, hyaline, smooth-walled, cylindrical to slightly inflated, opening 1–2 μm wide, collarette or periclinal thickening observed. Conidia 12.2–29.7 × 3–5 μm (x̄ = 17.7 × 3.8 μm, n = 15), L/W ratio 4.7, hyaline, smooth or verruculose, aseptate, curved, both sides gradually tapering towards the round to slightly acute apex and truncate base, guttulate. Appressoria not observed.
Culture characteristics: Colonies on PDA flat with entire margin, aerial mycelium sparse, short, pale olivaceous-grey, colony surface buff, some sectors dark grey-olivaceous to dark-olivaceous-grey, iron-grey acervuli can be observed mainly on the edge of the colony. Reverse olivaceous green, concentric rings can be clearly observed, reaching 40–55 mm in 7 days at 25 °C.
Material examined: ITALY, Province of Forlı`-Cesena [FC], Meldola, on a dead branch of Sambucus ebulus (Adoxaceae), 30 March 2016, Erio Camporesi IT 2902 (MFLU 16-2675, holotype); ex-type living culture, MFLUCC 16-1388, KUMCC 16-0127.
GenBank: ITS: KY098781, KY595193; GAPDH: KY098780, KY595192; CHS: KY098779, KY595190; Actin: KY098778, KY595190; TUB2: KY098782, KY595194 respectively.
Notes: Colletotrichum dematium species complex is mainly characterized by species with curved conidia (Damm et al. 2009, Jayawardena et al. 2016a, b). Colletotrichum sambucicola falls within the C. dematium species complex clade and forms a separate branch with 100% bootstrap support and 1.00 Bayesian posterior probability and is a sister taxon to C. anthrisci. Among the species with angular conidia, conidia of C. anthrisci have the highest L/W ratio (7.8) and the apex is strongly pointed. Colletotrichum sambucicola differs from C. anthrisci in having conidiogenous cells with a distinct collarette, as well as by having smaller conidia. A BLASTn search of NCBI GenBank with the ITS sequence of MFLUCC 16-1388 showed 99% similarity to quite a number of Colletotrichum species with angular conidia. The closet match in a BLASTn search in GenBank with the GAPDH sequence of MFLUCC 16-1388 was GenBank GU228237 (98% identity, three bp differences) and CHS GU228335 (98% identity 4–7 bp differences). The newly described taxon differs from its sister taxon C. anthrisci in six bp in ITS, eight bp in GAPDH, four bp in CHS, 39 bp in Actin, and four bp in TUB2 (Tibpromma et al. 2017).