Pseudocercospora haldinae Sanjay, Sanjeet & Raghv. Singh, 2021

Yadav, Sanjay, Verma, Sanjeet Kumar, Singh, Vinay Kumar, Singh, Raghvendra, Singh, Archana & Kumar, Shambhu, 2021, Morphology and phylogeny of a new species, Pseudocercospora haldinae (Mycosphaerellaceae) on Haldina cordifolia from India, Phytotaxa 501 (2), pp. 281-292 : 284

Pseudocercospora haldinae Sanjay, Sanjeet & Raghv. Singh sp. nov. ( Figs 1–4 )

MycoBank: MB832964

Diagnosis:— Conidia are catenate, highly septate, longer and wider compared to P. adinae , P. adinicola and P. ranjita .

Etymology:— The species epithet is derived from the name of the host genus.

Type:— INDIA. Uttarakhand: Srinagar, Garhwal, 30.2247° N, 78.7986° E, 27 December 2018, coll. Sanjay Yadav, on living leaves of Haldina cordifolia (Roxb.) Ridsdale (Rubiaceae) , AMH 10214 (holotype), MH-BHU 11(isotype), NFCCI 4806 (ex-type living culture).

Leaf spots amphigenous, subcircular to mostly irregular, 2–12 mm diam., later coalescing to cover entire surface of leaf, initially reddish brown, later blackish brown. Sexual morph: not seen. Asexual morph: Stromata welldeveloped, sub-epidermal to mostly erumpent, pseudoparenchymatous, mid-brown to dark brown, 36–56 × 24–46 µm diam. Conidiophores macronematous, densely fasciculate, unbranched, arising from stromata, erect to procumbent, divergent, smooth, slightly thick-walled, brown to dark brown, 10–30 × 2–4.5 µm, 0–3-septate. Conidiogenous cells integrated, terminal, mono-to polyblastic, 4–12.5 × 2–4.5 µm, loci slightly thickened and darkened, 1.3–2.6 µm wide. Conidia solitary to catenate, catenation simple to branched, dry, sympodial, mostly smooth or finely roughened, wall thin to slightly thickened, 0–24-transversely septate, oval to elliptical, cylindrical to fusiform, straight to slightly curved, obclavate to obclavate-cylindrical, base rounded to truncate, apex mostly obtuse, olivaceous to olivaceousbrown, 10–125 × 1.3–5.5 µm, ramoconidia subcylindrical to fusiform with 2−3 apical hila, hila 1.3–2.6 µm wide, slightly thickened and darkened.

Culture characteristics

Slow growing, colony on PDA attained a diameter of 38 mm after 6 weeks at 25±5° C, top colour dark greenish brown, reverse dark greenish black, regular, velvety, raised, surface folded, margin smooth and entire. Red coloured crystals did not form on media.

Figures

FIGURE 1. Symptoms of Pseudocercospora haldinae on Haldina cordifolia. a, b. Plant showing symptoms. c. Symptom on upper surface of leaf. d–f. Symptom on lower surface of leaf. Scale bars c–e = 10 mm, f = 2 mm.

FIGURE 2. Ex-type culture of Pseudocercospora haldinae (NFCCI 4806) on PDA after 6 weeks at 25±5°C. a. Top view. b. Reverse view. c, d. Mycelia.

FIGURE 3. Microphotographs of Pseudocercospora haldinae (AMH 10214, holotype). a–g. Fascicles of conidiophores with conidia on erumpent stromata. h, i. Polyblastic nature of conidiogenous cells (red arrows). Scale bars a–h = 20 µm, i = 10 µm.

FIGURE 4. Microphotographs of Pseudocercospora haldinae (AMH 10214, holotype). a–i. Different forms of conidia. j, k. Ramoconidia. l–o. Catenation in conidia. p. Germinating conidium. Scale bars a = 20 µm, b–p = 10 µm.