Diaporthe cameroonensis L. Schweizer, C. Lamb. & Y. Marin, 2023

Lambert, Christopher, Schweizer, Lena, Matio Kemkuignou, Blondelle, Anoumedem, Elodie Gisele M., Kouam, Simeon F. & Marin-Felix, Yasmina, 2023, Four new endophytic species of Diaporthe (Diaporthaceae, Diaporthales) isolated from Cameroon, MycoKeys 99, pp. 319-362 : 319

Diaporthe cameroonensis L. Schweizer, C. Lamb. & Y. Marin sp. nov.

Fig. 5

Etymology.

Named for the country where it was isolated from, Cameroon.

Description.

Conidiomata pycnidial in culture on PNA, globose or irregular, dark brown to black, solitary or in groups, embedded, erumpent, 220-550 μm diam, white to cream conidial drops exuded from ostioles; conidiomatal wall pale olivaceous green to olivaceous brown, composed of 1-3 layers, textura angularis. Conidiophores cylindrical to subcylindrical, tapering towards apex, base subhyaline to pale yellow or pale olivaceous, apex hyaline to subhyaline, straight, densely aggregated, smooth-walled, 1(-3) septate, 12.5-28 × 1-3.5 μm. Conidiogenous cells phialidic, cylindrical to subcylindrical, tapering towards apex, hyaline, terminal, 6-11(-12) × 1.5-3 μm. Paraphyses not observed. Alpha conidia ellipsoidal, hyaline, apex rounded, base rounded to slightly acutate, biguttulate, aseptate, 4.5-6 × (1-)1.5-2.5 μm. Beta and gamma conidia not observed.

Culture characters.

Colonies on PDA covering the surface of the Petri dish in 2 weeks, grayed yellow (161C-D) with transparent margins and white mycelia, cottony to slightly feathery, flat to raised in some zones, lobate, margins filamentous to fimbriate; reverse grayed yellow (161A-D) with transparent margins. Colonies on MEA covering the surface of the Petri dish in 2 weeks, grayed white (156A-B) with transparent margins and yellow white (158D) mycelia, or grayed-orange (165A) with white mycelia and yellow green (153D) margins, cottony to slightly feathery, flat to raised in some zones, margins filamentous to fimbriate; reverse grayed yellow (161A-D) with transparent margins or grayed orange (165A-B) with yellow green (153D) margins. Colonies on OA covering the surface of the Petri dish in 2 weeks, white with grayed white (156C) patches and grayed green (197D) or gray brown (199D) margins, or yellow green (152B) with brown (200A) patches and yellow-white (158A) mycelia, cottony to slightly feathery, flat to raised in some zones, margins filamentous to fimbriate; reverse grayed green (195A) with yellow green centre (152C) or fully yellow green (152C-D).

Specimens examined.

Cameroon, Kala Mountain , from Atractogyne gabonii , 02 Jan. 2019, E. G. M. Anoumedem (holotype CBS H-24922; culture ex-type CBS 148913 = STMA 18288); from Trema guineensis , 11 Apr. 2019, E. G. M. Anoumedem (STMA 18289); from Trema guineensis , 11 Apr. 2019, E. G. M. Anoumedem (STMA 18290) .

Notes.

Different strains belonging to this new species formed a well-supported independent clade (100 bs / 1 pp) apart from all surveyed Diaporthe spp. This species was isolated from Trema ( Cannabaceae ) and Atractogyne ( Rubiaceae ). To the best of our knowledge, this is the first Diaporthe species to be isolated from Atractogyne . Diaporthe pseudoanacardii , which is introduced further below, has also been isolated from Trema collected in Cameroon. However, both species can easily be distinguished by the length of their conidiogenous cells (12.5-28 μm in D. cameroonensis vs (7.5-)10-45 μm in D. pseudoanacardii ) and conidia (4.5-6 μm in D. cameroonensis vs (5-)6-8(-9) μm in D. pseudoanacardii ).

Figures

Figure 5. Diaporthe cameroonensis (ex-type strain CBS 148913) A conidioma in PNA B conidiomata in OA C conidiophores and conidia D alpha conidia. Scale bars: 100 μm (A); 500 μm (B); 5 μm (C, D).