Cadophora africana Damm & S.Bien, 2020

Bien, Steffen & Damm, Ulrike, 2020, Arboricolonus simplex gen. et sp. nov. and novelties in Cadophora, Minutiella and Proliferodiscus from Prunus wood in Germany, MycoKeys 63, pp. 119-161 : 119

Cadophora africana Damm & S.Bien sp. nov. Figures 5B , 7

Type.

South Africa, Western Cape Province, Franschhoek, from necrosis in wood of Prunus salicina close to old pruning wound, 10 June 2004, U. Damm leg., CBS H-19984 - holotype; GLM-F117479 - isotype; CBS 120890 = STE-U 6203 = GLMC 1892 - culture ex-type.

Etymology.

Named after the continent of origin, Africa.

Description.

Sexual morph not observed. Asexual morph on SNA. Vegetative mycelium hyaline, smooth-walled, septate, branched, 1-3 µm wide, hyphal cells sometimes inflated and constricted at the septa, sometimes becoming brown with age, chlamydospores absent. Sporulation abundant, conidia formed on hyphal cells. Conidiophores hyaline, smooth-walled, mesotonously branched, occasionally with acropleurogenous branching, up to 35 µm long. Conidiogenous cells enteroblastic, hyaline, smooth-walled, discrete conidiogenous cells cylindrical to navicular, often constricted and sometimes widened at the base, 8-18 × 1.5-3 µm, necks cylindrical, 1-2 × 1-1.5 µm, collarettes distinct, cylindrical to narrowly funnel-shaped, 0.5-1.5 µm long, 1-1.5 µm wide at the upper edge, opening 1-1.5 µm wide, periclinal thickening observed. Conidia aggregated in heads, hyaline, smooth-walled, aseptate, mostly globose to subglobose or obovoid to tear-shaped, sometimes ellipsoidal, (2-)2.5-4(-4.5) × (1.5-)2-2.5(-3) µm, mean ± SD = 3 ± 0.5 × 2.1 ± 0.2 µm, L/W ratio = 1.4.

Culture characteristics.

Colonies on SNA flat with an entire to undulate margin, white to buff, sometimes grey olivaceous to olivaceous, lacking aerial mycelium, reverse same colours, 6-14 mm diam. in 2 wk (25 °C in the dark); Colonies on OA flat with an entire to undulate margin, primrose to amber, grey olivaceous to olivaceous black, often with a white margin, partly covered by floccose white aerial mycelium, reverse buff to grey olivaceous, 22-30 mm diam. in 2 wk (25 °C in the dark); Colonies on PDA flat to raised, entire edge, short aerial mycelium, pale buff, after> 2 wk with pale olivaceous to pale olivaceous grey patches or sectors, reverse same colours, 30 mm diam. in 2 wk (20 °C). Colonies on MEA flat to low umbonate, with entire edge, abundant velvety aerial mycelium, mycelium and surface white to very pale smoke-grey; reverse very pale luteous, ochreous to buff, in diffuse daylight with concentric oliveceous-grey rings, 30 mm diam. in 2 wk (20 °C).

Notes.

Cadophora africana was isolated once from P. salicina in South Africa. Cadophora africana , as well as C. bubakii and C. ramosa , form subglobose conidia. However, conidia of C. africana are mostly globose to subglobose, sometimes even tear-shaped, while those of C. ramosa are often ellipsoidal, elongate-ellipsoidal to cylindrical and the portion of subglobose conidia in C. bubakii is comparatively low. Therefore, conidia of both species are on average longer (4.9 µm and 3.6 µm, respectively) than those of C. africana (3 µm) and with a larger L/W ratio (2.2 and 2.1, respectively; C. africana : 1.4).

The ITS sequence of C. africana strain CBS 120890 differs in eleven nucleotides from the ex-type strain of C. prunicola and in nine nucleotides, both from the ex-type strain of C. novi-eboraci NYC14 and from strain CBS 101359. The differences to these strains exceed 30 and 18 nucleotides in the TUB and EF-1α sequences, respectively. The closest match in a blastn search with the ITS sequence of C. africana is strain NYC13 of C. novi-eboraci (identity 98.48%), which is included in our phylogeny.

Figures

Figure 5. Colony surface of analysed strains on OA medium. A Arboricolonus simplex GLMC 459 T B Cadophora africana CBS 120890 T C C. bubakii CBS 198.30 T D C. luteo-olivacea GLMC 1264 E C. novi-eboraci GLMC 1472 F C. obscura CBS 269.33 G C. prunicola CBS 120891 T H C. prunicola GLMC 1633 I C. ramosa GLMC 377 T J Minutiella pruni-avium GLMC 1624 T K Proliferodiscus ingens GLMC 1751 T L Proliferodiscus sp. GLMC 460. Cultures A, J-L after 4 wk. Cultures B-I after 2 wk. Strains with a superscript T are ex-type cultures.

Figure 7. Cadophora africana sp. nov. A-G conidiophores and conidiogenous cells (arrow indicates a short neck) H conidia A-H from SNA A-H LM. Scale bar: 5 μm (A applies to B-H).