Pseudocercospora sophoricola M. Bakhshi, Arzanlou

Bakhshi, Mounes, Arzanlou, Mahdi, Babai-Ahari, Asadollah, Groenewald, Johannes Z. & Crous, Pedro W., 2014, Multi-gene analysis of Pseudocercospora spp. from Iran, Phytotaxa 184 (5), pp. 245-264 : 256

Pseudocercospora sophoricola M. Bakhshi, Arzanlou , Babai-ahari & Crous, sp. nov. ( Fig. 7 ) MycoBank MB 809998

Type:— IRAN. Zanjan Province: Tarom, Guilankeshe, on Sophora alopecuroides L. ( Fabaceae ), October 2011, M. Bakhshi (holotype IRAN 16463 F, culture ex-type CCTU 1037 = CBS 136020).

Description in planta:— Leaf spots distinct, amphigenous, circular to subcircular, 1–6 mm diam., pale brown in centre, with raised, dark brown to black border. Mycelium internal. Caespituli predominantly hypophyllous, dark brown on leaves. Stromata moderately developed, substomatal to intraepidermal, semi-immersed, globular, 10–30 μm diam. Conidiophores medium brown, arranged in moderately dense fascicles, smooth, unbranched, straight, doliiform or lageniform to short cylindrical, 0–1-septate, (8–)13–16(–22) × (3–)4.5–5(–6) μm, predominantly reduced to conidiogenous cells, apex subtruncate. Conidiogenous cells medium brown, smooth, proliferating sympodially, tapering to flat-tipped apical loci, loci unthickened to slightly thickened and somewhat darkened, 1–3 μm diam. Conidia solitary, medium to dark brown, guttulate, thick-walled, sometimes constricted at septa, subcylindrical to obclavate, apex obtuse to sub obtuse, base obconically truncate, straight to gently curved, conspicuously 1–8-septate, (20–)50–70(–110) × (2.5–)3.5–4(–5) μm; hila unthickened to slightly thickened and somewhat darkened and refractive, 1–2.5 μm diam.

Cultural characteristics:— Colonies on MEA slow growing, reaching 15 mm diam. after 20 days at 25 ºC in the dark; surface velvety, smooth to folded, erumpent with sparse aerial mycelium and even margins. Dark brown to black on the surface, black underneath.

Habitat/Distribution:— Known to inhabit Sophora alopecuroides , Zanjan Province, Iran.

Etymology:— Named after the host genus from which it was collected, Sophora .

Other material examined:— IRAN. Zanjan Province: Tarom, Guilankeshe , on Sophora alopecuroides , October 2011, M . Bakhshi ( CCTU 1037.2 ) .

Notes:— Pseudocercospora sophoricola must be regarded as a new species based on its distinct phylogenetic position ( Fig. 2 ). In the individual gene trees, it is distinguished in the ITS (sister taxon to P. ocimi-basilici ), ACT (sister taxon to P. udagawana ) and TEF1-α (sister taxon to P. udagawana ) phylogenies. In the combined tree ( Fig. 2 ), it is a sister taxon to P. udagawana . Pseudocercospora sophoricola is morphologically well distinguished from P. sophorae ( Guo & Liu 1991) in having narrower stromata, wider conidiophores which are mostly reduced to conidiogenous cells, slightly thickened and somewhat darkened conidiogenous loci and medium to dark brown, somewhat wider and longer, distinctly septate conidia . Furthermore, P. sophorae forms in vivo superficial hyphae with solitary conidiophores. This is the first species of the genus Pseudocercospora described from Sophora alopecuroides .

Figures

FIGURE 2. A Bayesian inference phylogenetic tree of 59 isolates of Pseudocercospora. The tree was built using concatenated sequences of the ITS, ACT and TEF1-α loci, each with a separate model of DNA evolution. Species clades from Iran are indicated in green coloured blocks and species names in black text. Culture accession numbers are listed along with host plant (orange text) and place of origin (dark blue text). The tree was rooted to Passalora eucalypti (CBS 111318). Bayesian posterior probabilities ≥ 0.95 are indicated with colourcoded branches and scale bar indicates number of expected changes per site.

FIGURE 7. Pseudocercospora sophoricola. a. Leaf spots. b. Globular stromata. c–e. Fasciculate conidiophores reduced to conidiogenous cells. f–l. Conidia. Scale bars = 10 µm.