Cladosporium guizhouense S. Y. Wang, Yong Wang bis & Y. Li

Cladosporium guizhouense S. Y. Wang, Yong Wang bis & Y. Li , MycoKeys 91: 151–168 (2022) sp. nov.

Fig. 5 View Figure 5

Description.

Parasitic on aphids from Telosma cordata (Burm. f.) Merr. ( Apocynaceae ). Sexual morph: Not observed. Asexual morph: Hyphomycetous.

Mycelium superficial and immersed, with abundant sporulation on the surface of aphids. Conidiophores erect, fasciculate, macronematous, cylindrical, subnodulose or nodulose, geniculate, septate, branched, pale brown, slightly roughened to verruculose, thick-walled, and pronounced loci, 111–367 × 3.5–5 μm. Conidiogenous cells integrated, terminal or intercalary, cylindrical, cylindrical-oblong, sometimes geniculate, 20–65 × 3–6 μm, conidiogenous loci at the apex (2–5) or in lateral shoulders (0–4). Ramoconidia olive-green, 0–4 - septate, ellipsoidal to subcylindrical, smooth- and thick-walled, 10–26 × 3.5–7.5 μm. Secondary ramoconidia pale brown, oblong, oblong-ellipsoid, 0–1 septate, 1–4 distal hila, 8.5–13.5 × 3.5–7.5 μm. Conidia numerous, catenate, forming short branched chains, aseptate, olive to light olive, smooth- and thin-walled, variable in size and shape, ellipsoid-ovoid, obovoid, and fusiform, 4–10 × 3–6.5 μm. Intercalary conidia aseptate, olive to light olive, ellipsoid-ovoid, fusiform, 6–10 × 4–6.5 μm. Terminal conidia aseptate, olive to light olive, obovoid, 4–6.5 × 3–5.5 μm. Microcyclic conidiogenesis absent. In vitro on SNA: Mycelium abundant, submerged, overgrowing whole culture dishes, hyphae straight to slightly sinuous, septate and branched, light olive-green to olive-green, and thick-walled, 1.5–4.5 µm wide. Conidiophores erect, branched, light olive-green, thick-walled, 43–163 × 2.5–4 µm. Ramoconidia pale olivegreen, narrowly ellipsoid to cylindrical-oblong, subcylindrical, septate or aseptate, smooth- and thick-walled, 6–27 × 3–5 µm. Conidia in simple and branched acropetal chains, light olive, aseptate, smooth- and thin-walled, variable in size and shape, ellipsoid-ovoid, obovoid, fusiform, 3–8 × 2.5–4 µm. Intercalary conidia light olive, aseptate, smooth- and thin-walled, mostly ellipsoid, 3.5–8 × 2.5–4 µm. Terminal conidia light olive, aseptate, smooth- and thin-walled, mostly ovoid, 3–4.5 × 2.5–3.5 µm.

Culture characteristics.

All conidia can germinate within 12 h in sterile distilled water, with tubes forming from any part. Colonies on MEA attaining 35–45 mm diameter, after 1 week at 25 ° C, dark green, white to greyish toward regular margins, velvety, sporulation profuse, radially furrowed, aerial mycelium abundant, reverse dark green. Colonies on PDA attaining 30–40 mm diameter, after 1 week at 25 ° C, greyishgreen, greyish toward irregular margins, velvety, sporulation profuse, radially furrowed, aerial mycelium abundant, reverse dark green. Colonies on OA attaining 30–40 mm diameter, after 1 week at 25 ° C, greyish olivaceous, white toward irregular margins, sporulation profuse, reverse olivaceous. Colonies on SNA attaining 25–30 mm diameter, after 1 week at 25 ° C, olivaceous, flat, white toward regular and wide margins, aerial mycelium loose, reverse olivaceous.

Host.

Aphids ( Aphididae ), leaves of plants, and uredinia of Hemileia vastatrix ( Pucciniaceae ).

Habitat.

In tropical and subtropical regions, it can infect insects, act saprophytically on plant tissues, and function as a fungicolous fungus on the uredinia of rust. During the middle and late stages of aphid damage, numerous aphids die on the underside of plant leaves, becoming enveloped in mycelial tissue.

Distribution.

China, Sichuan Province, Guangan City. China, Guizhou Province, Guiyang City. Ethiopia, Oromia Region, Illubabor Gore. Brazil, Minas Gerais, Viçosa.

Material examined.

CHINA • Sichuan Province, Guangan City , Yuechi County. Infected aphids were found on the underside of the leaves of Telosma cordata , 30°44.18 "N, 106°30.80 "E, alt. 480 m, 31 Jan. 2020, X. L. Xu, XXL 202001003 ( SICAU 25-0076 , living culture SICAUCC 25-0057 ) ; • ibid. XXL 202001003-1 ( SICAU 25-0077 , living culture SICAUCC 25-0058 ) .

Notes.

Phylogenetically, our collections grouped with isolates of Cladosporium guizhouense within the C. cladosporioides complex, showing strong statistical support (92 % MLBS, 0.97 BIPP) (Fig. 1 View Figure 1 ). A total of 6 bp nucleotide differences were observed between our isolate SICAUCC 25-0057 and the ex-type culture of C. guizhouense (GUCC 401.7), with 0 bp in ITS, 2 bp in act, and 4 bp in tef 1 - α ( Wang et al. 2022 b). Morphologically, our isolate is fully consistent with C. guizhouense , showing no noticeable differences ( Wang et al. 2022 b; Pereira et al. 2024).