Paramicrosphaeropsis vitis Abdollahz., Amirash., S. Piri & Bashiri, in Dong et al., Fungal Diversity (2025)
Index Fungorum number: IF 902575; MycoBank number: MB 902575; Facesoffungi number: FoF 17153; Fig. 1
Etymology – the epithet refers to the host plant genus, Vitis, from which the species is isolated.
Holotype – IRAN 18587F
From vineyards showing grapevine trunk disease symptom. Sexual morph: undetermined. Asexual morph: Hyphae branched, septate, hyaline to pale brown. Conidiomata (67–)90–140(–291) µm diam. (x̄= 131 µm, n = 50), pycnidial, globose to subglobose, immersed, sometimes semi-immersed, mostly solitary, sometimes aggregated, first hyaline, pale brown to brown at maturity, ostiolate. Ostiole central, erumpent, somewhat papillate. Conidiomatal wall pseudoparenchymatous, thin, composed of several layers of brown cells of textura angularis. Conidiophores mostly reduced to conidiogenous cells. Conidiogenous cells enteroblastic, phialidic, globose to subglobose, ampulliform or lageniform to doliiform, hyaline, smooth-walled. Conidia (4.7–)5–7(–8.9) × (2.9–)3.3–4.5(–5.4) µm x̄ = 6 × 3.9 µm, n = 100), variable in shape, ellipsoid, subcylindrical, obpyriform, straight to slightly curved, aseptate, first hyaline, becoming pale brown, yellowish brown or greenish brown with age, guttulate, smooth-walled, thin-walled. Chlamydospores (5.6–)8–12(–15.5) × (3.8–)6–9(–10.6) µm (x̄ = 10.3 × 7.6 µm, n = 100), mostly in chains, rarely solitary, globose to subglobose, or ellipsoid, mostly aseptate, rarely 1-septate, pale brown to brown, smooth-walled, thick-walled.
Culture characteristics – colonies on PDA reaching 63 mm diam. after 14 days at 25 °C in dark, flat with aerial mycelia, margins entire, regular, at the surface white to pale pinkish, greenish olivaceous at some part, at the reverse white to pale pinkish. Colonies on MEA reaching 32 mm diam. after 14 days at 25 °C in dark, colonies flat with sparse aerial mycelia, margins undulate, irregular, wrinkle at the surface, pinkish at the surface and reverse. Colonies on OA reaching 56 mm diam. after 14 days at 25 °C in dark, flat with aerial mycelia, margins entire, regular, white to pale pinkish at the surface and reverse.
Material examined – Iran, West Azarbaijan Province, Sardasht, Mirabad, Musalan Village (36° 22′ 34.4″ N, 45° 23′ 56.2″ E), from cordons and trunks of Vitis vinifera, 20 August 2022, P. Amirashayeri (IRAN 18587F, holotype); ex-type culture, IRAN 5248C = CJAPA90; ibid., Shivashan Village (36° 25′ 07.8″ N, 45° 21′ 41.0″ E), from cordons and trunks of Vitis vinifera, 31 August 2022, Amirashayeri, living culture, CJAPA22; ibid., Bariteh Village (36° 21′ 39.0″ N, 45° 24′ 34.4″ E), from cordons and trunks of Vitis vinifera, 15 September 2022, P. Amirashayeri, living culture, CJAPA37; ibid., Yasinabad Village (36° 07′ 08.9″ N, 45° 32′ 45.4″ E), from cordons and trunks of Vitis vinifera, 26 September 2022, P. Amirashayeri, living culture, CJAPA49; ibid., Sureh Chum Village (36° 06′ 25.0″ N, 45° 25′ 09.5″ E), from cordons and trunks of Vitis vinifera, 5 October 2022, P. Amirashayeri, living culture, CJAPA63; ibid., Faqer Khadariyan Village (36° 08′ 07.0″ N, 45° 29′ 23.0″ E), from cordons and trunks of Vitis vinifera, 3 August 2023, P. Amirashayeri, living culture, CJAPA89; ibid., Halveh Village (36° 15′ 01.6″ N, 45° 28′ 16.3″ E), from cordons and trunks of Vitis vinifera, 23 August 2023, P. Amirashayeri, living culture, CJAPA116; Kermanshah Province, Kermanshah, Kouzaran, Nilavareh-ye Olya Village (34° 35′ 20.9″ N, 46° 31′ 04.1″ E), from cordons and trunks of Vitis vinifera, 11 September 2020, S. Piri, living culture, CJASPN621.
GenBank accession numbers – IRAN 5248C = ITS: PQ238302, rpb2: PQ240637, tub2: PQ240634; CJASPN621 = ITS: PQ238301, rpb2: PQ240636, tub2: PQ240635.
Notes – in our phylogenetic tree, Paramicrosphaeropsis vitis is closely related to P. zagrosensis, a species recently discovered in Iran. The two species exhibit genetic differences in rpb2 (eight substitutions) and tub2 (three substitutions) sequence data, and are separated in both single-gene and multigene phylogenetic analyses (Fig. 2). Morphologically, P. vitis (x̄ = 6 × 3.9 µm, n = 100) has slightly longer and narrower conidia than P. zagrosensis (x̄= 5.7 × 4 µm, n = 50). Although it is difficult to distinguish between these two species based on micromorphology alone, the growth rate of P. vitis is faster than P. zagrosensis on PDA (36 mm/7 days vs. 15–17 mm/8 days) and OA (36 mm/7 days vs. 23–25 mm/8 days) at 25 °C. In addition, the presence of abundant aerial hypha in P. vitis on PDA and OA, along with the absence of chlamydospores in P. zagrosensis can serve as useful distinguishing characteristics between the two species. Paramicrosphaeropsis vitis is the first species isolated from Vitis species within the genus and is associated with grapevine trunk diseases.
Figure 1 – Paramicrosphaeropsis vitis (IRAN 18587F, holotype). a–c Colonies on PDA, OA, and MEA at 25 °C in dark after 14 days, respectively. d Pycnidia on PDA. e, f Pycnidia in two different focal planes. g–i Conidiogenous cells. j–l Conidia. m Chlamydospores. Scale bars: d = 500 µm, e, f = 20 µm, g–i, k–m = 5 µm, j = 10 µm.
Figure 2 – Maximum likelihood consensus tree inferred from the combined ITS, rpb2, and tub2 multiple sequence alignments. Bootstrap support values for maximum likelihood (ML, first value) equal to or greater than 50% and Bayesian posterior probabilities from MCMC analyses (BYPP, second value) equal to or greater than 0.95 are given nearby the nodes. The scale bar indicates expected changes per site. The tree is rooted to Vacuiphoma ferulae (CBS 353.71). Ex-type strains are indicated with “T”. The newly generated sequences are indicated in red.