Pseudocercospora atromarginalis (G.F. Atk.) Deighton, Mycol. Pap.

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 : 250-253

Pseudocercospora atromarginalis (G.F. Atk.) Deighton, Mycol. Pap. 140: 139. 1976 ( Fig. 3 )

Additional synonyms in Crous et al. (2013a)

Description in planta:— Leaf spots amphigenous, subcircular to irregular, 2–12 mm diam., olivaceous-green. Mycelium internal. Caespituli predominantly hypophyllous. Stromata well-developed, substomatal to intraepidermal, semi-immersed, 15–30 μm diam. Conidiophores arranged in moderately dense fascicles, arising from stromata, through stomata or erumpent through the cuticle, medium brown, smooth, 1–6-septate, unbranched, straight to curved, subcylindrical, regular in wide, (15–)45–60 × 4–5 μm. Conidiogenous cells terminal, medium brown, smooth, proliferating sympodially, (8–)10–15(–25) × 3.5–4(–5) μm, loci neither thickened nor darkened. Conidia solitary, pale brown, subcylindrical to obclavate, apex obtuse to subobtuse, base obconically truncate, straight to gently curved, 1–8- septate, (18–)42–55(–85) × 3–4.5 μm; hila neither thickened nor darkened or refractive, 1–2.5 μm diam.

Habitat/Distribution:— Known to inhabit Capsicum annuum , Capsicum sp. , Lycianthes biflora , Physalis peruviana , Solanum aethiopicum , S. alatum , S. americanum , S. aviculare , S. biflorum , S. gracile , S. laciniatum , S. nigrum , S. nodiflorum , S. photeinocarpum , S. pseudocapsicum , S. torvum , S. xanthocarpum (Solanaceae) , worldwide including Australia, Barbados, Bermuda, Brazil, China, Colombia, Cook Island, Costa Rica, Cuba, Dominican Republic, Ethiopia, Fiji, Hong Kong, India, Iran, Jamaica, Japan, Kenya, Korea, Libya, Mauritius, Malawi, Myanmar, New Caledonia, New Zealand, Niue, Pakistan, Panama, Philippines, Puerto Rico, Senegal, Solomon Islands, South Korea, Sri Lanka, Sudan, Taiwan, Thailand, Trinidad and Tobago, USA (AL, WL), Vanuatu, Virgin Islands, Zambia, Zimbabwe ( Crous & Braun 2003, Farr & Rossman 2014).

Material examined:— IRAN. Ardabil Province: Moghan, on Solanum nigrum L. ( Solanaceae ), October 2011, M. Bakhshi ( CCTU 1052). Moghan, on S. nigrum , October 2011, M. Bakhshi ( CCTU 1056 = CBS 136112). Moghan, on S. nigrum , October 2011, M. Bakhshi ( CCTU 1091). Mazandaran Province: Ramsar, Kotra, on S. nigrum , October 2012, M. Bakhshi ( CCTU 1193).

Notes:— Pseudocercospora atromarginalis could not be distinguished from P. chengtuensis and P. fuligena based on DNA sequences of ITS, ACT and TEF 1-α. Due to the availability of HIS sequence data of P. fuligena , and RPB2 and TUB sequences of P. atromarginalis in NCBI’s GenBank sequence database, we also sequenced these loci for our isolates. Based on these genes, our isolates could be confirmed as P. atromarginalis .

Pseudocercospora mazandaranensis M. Bakhshi, Arzanlou , Babai-ahari & Crous, sp. nov. ( Fig. 4 ) MycoBank MB 809996

Type:— IRAN. Mazandaran Province: Tonekabon, on Nerium oleander L. ( Oleaceae ), June 2012, M. Bakhshi (holotype IRAN 16462 F, culture ex-type CCTU 1102 = CBS 136115).

Description in planta:— Leaf spots amphigenous, irregular to angular, 5–50 mm diam., distinct, grey-brown, predominantly occurring at leaf margin or close to leaf tip, but smaller spots are scattered over the whole leaf lamina, border definite, raised, with dark purple-brown to dark brown border. Mycelium internal. Caespituli sporodochial, predominantly hypophyllous, evenly distributed over the leaf spot, punctiform, olivaceous-brown on leaves, floccose. Stromata well-developed, erumpent to superficial, globular, medium brown to brown, 40–110 μm diam. Conidiophores medium brown, becoming paler toward the apex, aggregated in dense sporodochial fascicles, smooth to granular, 0–6- septate, branched, straight to curved, subcylindrical, (20–)42–52(–75) × 3–4(–5) μm. Conidiogenous cells terminal or lateral, pale brown, smooth, 10–35 × 3–3.5(–5) μm, proliferating sympodially, loci unthickened, nor darkened, 1–2.5 μm diam. Conidia solitary, pale brown to medium brown, guttulate, subcylindrical to obclavate, apex subobtuse to subacute, base obconically truncate to truncate, straight to curved, 1–8-septate, (17–)36–46(–65) × 2–3.5 μm; hila not thickened nor darkened, 1–2.5 μm diam.

Cultural characteristics:— Colonies on MEA reaching 26 mm diam. after 20 days at 25 ºC in the dark; surface smooth to folded, erumpent with sparse aerial mycelium and even margins. Surface olivaceous-grey, reverse iron-grey.

Habitat/Distribution:— Known to inhabit Nerium oleander , Mazandaran and Guilan Provinces, Iran .

Etymology:— Named after the province where the type was collected, Mazandaran, Iran.

Other material examined:— IRAN. Guilan Province: Rasht , on Nerium oleander , July 2012, M . Bakhshi ( CCTU 1146 ) .

Notes:— Three species of Pseudocercospora , namely P. neriella , P. neriicola and P. kurimensis have to date been described from leaf spot diseases on Nerium oleander ( Crous & Braun 2003, Crous et al. 2014). Pseudocercospora mazandaranensis is morphologically distinct from all three. Pseudocercospora neriella has internal mycelium, epiphyllous conidiomata, and wider conidia (15–50 × 3–5(–6) µm) with obtuse apices ( Braun 1996). Pseudocercospora neriicola has amphigenous, sporodochial conidiomata, longer conidia ((25–)50–60(–80) × 3(–3.5) μm, (3–)5–7(–10)- septate), and is also phylogentically distinct ( Crous et al. 2014). Pseudocercospora kurimensis has internal and external mycelium, hypophyllous conidiomata (or solitary conidiophores on secondary mycelium), and narrowly obclavate, 20–115 × 2–5 µm, 3–11-septate conidia ( Braun 1996) . Pseudocercospora mazandaranensis is also phylogenetically distinct from other known species of Pseudocercospora , and clusters adjacent to a clade containing P. cornicola , P. eupatoriella and P. lilacis ( Fig. 2 ).

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 3. Pseudocercospora atromarginalis. a. Leaf spots on upper and lower leaf surface. b–c. Fasciculate conidiophores. d–g. Conidia. Scale bars = 10 µm.

FIGURE 4. Pseudocercospora mazandaranensis. a. Leaf spots. b. Close-up of leaf spot with fruiting. c–d. Fasciculate conidiophores. e. Branched conidiophores. f–i. Conidia. Scale bars = 10 µm.