Cladosporium pseudotenuissimum P. P. Costa, A.W.C. Rosado & O.L. Pereira

Costa, Pricila P., Rosado, André W. C. & Pereira, Olinto L., 2022, Six new species of Cladosporium associated with decayed leaves of native bamboo (Bambusoideae) in a fragment of Brazilian Atlantic Forest, Phytotaxa 560 (1), pp. 1-29 : 21-24

Cladosporium pseudotenuissimum P. P. Costa, A.W.C. Rosado & O.L. Pereira sp. nov. ( Figure 7 )

MycoBank: MB840952

Systematic position: Fungi, Ascomycota, Pezizomycotina, Dothideomycetes, Dothideomycetidae, Cladosporiales, Cladosporiaceae

Etymology:—Name refers to phylogenetic proximity to C. tenuissimum .

Colonies on PDA attaining 71 mm diam, dull green, flat, woolly; smoke grey aerial mycelium; reverse olivaceous grey to dull green. Colonies on MEA attaining 62 mm diam, grey olivaceous to smoke grey, fluffy, woolly; reverse dull green to iron grey. Colonies on OA attaining 34 mm diam, grey olivaceous to olivaceous, greenish glaucous at the border, velvet, streaked with grooves, sector formation dull green, reverse grey olivaceous. Colonies on SNA attaining 39 mm diam, isabelline to buff, very scarce, sector formation; reverse similar to surface. Mycelium diffuse, branched, 1.88–5.56 μm wide, septate, slightly swollen, pale brown to brown, sometimes irregularly rough-walled to verrucose, with some bubble-like swelling. Conidiophores numerous, solitary, macronematous, 43.38–299.42 × 2.77–4.60 μm, arising mainly laterally and rarely terminally from hyphae, erect or flexuous, cylindrical, cylindrical oblong, sometimes cylindrical attenuated towards the apex, or almost filiform, sometimes head-like swollen or occasionally with peg-like prolongations, some slightly geniculate with loci formed on the lateral shoulder, brown to dark brown, rarely dichotomically branched, 0–7 septate, septa darker and thicker toward the base, micronematous laterally, 20.7–24.7 × 4.04–5.06 μm, pale brown, cylindrical or cylindrical attenuated to apex, 1 apical locus, aseptate, reduced to conidiogenous cells. Conidiogenous cells integrated, mostly terminal, cylindrical or cylindrical attenuated to apex, sometimes terminal head-like swollen, 15.25–51.03 × 2.77–4.01 μm, rarely geniculate towards the apex with a single locus on the small lateral shoulder, brown to dark brown, sometimes pale brown, commonly 1–4 loci, rarely more at the apex, conidiogenous loci non-protuberant or only slightly so, sometimes lightly thickened and darkened. Ramoconidia occasionally formed, oblong-ellipsoid, cylindrical, 33.31–53.21 × 4.54–5.09 μm, aseptate, truncate base, brown to dark brown. Secondary ramoconidia ellipsoid, cylindrical-oblong, sometimes ovoid, 1–4 distal hila, 7.05–20.27 × 2.77–5.86 μm, 0–1 septate, pale brown to brown, darkened, slightly protuberant. Conidia numerous, sometimes catenate, acrogenous, fusiform, ellipsoid, ellipsoid-ovoid, ellipsoid-cylindrical, subglobose, limoniform, oblong, oblong-ellipsoid, aseptate, occasionally 1-septate, subhyaline, pale brown to dark brown, 4.27–6.95 × 2.24– 3.74 μm, terminal conidia ovoid to subglobose 3.09–4.90 × 1.96–3.59 μm. Microcyclic conidiogenesis occurs.

Type:— Brazil. Minas Gerais: Araponga, at “ Parque Estadual Serra do Brigadeiro ”, isolated from decayed leaf of Chusquea urelytra (Poaceae) , March 15, 2016 (holotype VIC 44422 , ex-type culture COAD 2266) .

GenBank: MT373132 (ACT), MT680211 (TEF1-α), MZ318439 (rDNA-ITS)

Additional specimens examined:— BRAZIL. Minas Gerais:Araponga, at “Parque Estadual da Serra do Brigadeiro”, isolated from decayed leaves of Chusquea urelytra (Poaceae) , 15 March 2016, (living culture COAD 2264, COAD 2267 and COAD 2268), and isolated from decayed leaves of Chusquea anelytroides (Poaceae) , 15 March 2016 (living culture COAD 2259).

Notes:— Cladosporium pseudotenuissimum is phylogenetically close but distinct from C. tenuissimum . Moreover, some conspicuous morphological features distinguish the two species. Cladosporium tenuissimum have conidiophores solitary or in groups of 2–3, often are subnodulose or nodulose with apical and sometimes a few additional swellings on a lower level and have intercalary conidiogenous cells. While in C. pseudotenuissimum was only found solitary conidiophores, with swelling and conidiogenous cells restricted to the apex.Also, C. pseudotenuissimum has secondary ramoconidia, and its conidia are shorter (4.27–6.95 μm) than those described for C. tenuissimum [4–12(17)] μm. Cladosporium pseudotenuissimum also has bubble-like swelling on hyphae, which has not been described in any other species of Cladosporium until the moment.

Figures

FIGURE 7. Cladosporium pseudotenuissimum (VIC 44422, holotype). A–D. Colonies on A. Potato dextrose agar; B. Malt extract agar; C. Oatmeal agar; D. Synthetic nutrient-poor agar, after 14 days at 25 ºC, under near-ultraviolet light, respectively. E–J. Macronematous conidiophores and conidia. E, F. Micronematous conidiophores at arrows. K. Conidiogenous cel with conidia. L. Bubble-like swelling details. M. Microcyclic conidiogenesis (black arrow) and Ramoconidia (red arrow). Scale bars: E = 50 µM; F–M = 20 µM.