Curvularia geniculata (Tracy & Earle) Boedijn, Bull. Jard. bot. Buitenz, 3 Sér. 13(1): 129 (1933)

Index Fungorum number: IF 265873; MycoBank number: MB 265873; Facesoffungi number: FoF 16747; Figs. 1, 2

Endophytes on Citrus reticulata. Sexual morph: not observed. Asexual morph: Colonies on PDA, the hyphae were 2.3–3.2 µm wide, septate, transparent, and branched. Conidiophores macronematous, mostly arising from creeping hyphae, brown, septate, simple or branched, erect or curved, with a knee-shaped top, smooth walls, 115–250 × 4–5.5 µm (x̄ = 170 × 4.5 µm, n = 10). Conidiogenous cells light to medium brown, with smooth walls, subcylindrical or cylindrical, occasionally swollen, terminal or intercalary, 6–14 × 3.5–5.5 µm (x̄= 9 × 5 µm, n = 20). Conidia apical and basal cells transparent to light brown, mature conidia middle medium brown to dark brown and swollen, straight or slightly curved, ovate or pear-shaped or fusiform, mostly 4-septate, a few 3-septate, smooth-walled, 15–27 × 7–12 µm (x̄ = 22 × 9.5 µm, n = 30). Hilum obvious, prominent, 1–2 µm wide, black.

Culture characteristics – colonies on PDA reaching 66–76 mm diam., at 25 °C after 7 days, the colony is round, with complete edges and cottony hyphae; from above, medium gray-green; from below, gray-black, and there are white hyphae circles in the middle and edges. Colonies on MEA reaching 59–69 mm diam., at 25 °C after 7 days, the colony is round, with complete edges and flat; from above, light yellow, the middle part is white and has abundant hyphae, the edge hyphae is sparse and white; from below, brown.

Material examined – CHINA, Guangdong Province, Shaoguan City, on Citrus reticulata, July 2021, Z. Zheng & I.S. Manawasinghe, MHZU 24–1190, living cultures ZHKUCC 24–1818, ZHKUCC 24–1819.

GenBank – ZHKUCC 24–1818: PV290841 (ITS); ZHKUCC 24–1819: PV290842 (ITS).

Notes – The phylogenetic results showed that our isolate clustered with C. geniculata (Fig. 2). Conidia of our isolate strain are similar to C. geniculate (USJCC-0073) with 3–4 septate, smooth-walled (Boedijn 1933). Therefore, we identified our isolate as C. geniculata. In this study, C. geniculata was reported on Citrus reticulata for the first time.

Figure 1 – Curvularia geniculata (ZHKUCC 24–1818). a Upper and reverse side of cultures on PDA after seven days. b Upper and reverse side of cultures on MEA after seven days. c conidioma. d Stromata. e–g Conidiophores. h–m Conidia. Scale bars: e–m = 10 µm.

Figure 2 – Maximum Likelihood consensus tree inferred from the combined ITS, gapdh and tef1 multiple sequence alignments. Bootstrap support values for Maximum Likelihood (ML, first value) equal to or greater than 80% and Bayesian posterior probabilities from MCMC analyses (BYPP, second value) equal to or greater than 0.95 are given above the nodes. The scale bar indicates expected changes per site. The tree is rooted in Bipolaris maydis (CBS 136.29) and B. panici miliacei (CBS 199.29). Ex-type strains are indicated with “T”. The newly generated sequences are indicated in red.