Curvularia geniculata (Tracy & Earle) Boedijn

Yang, Erfu, Karunarathna, Samantha C., Priyashantha, Alviti Kankanamalage Hasith, Promputtha, Itthayakorn, Chen, Xuemei, Elgorban, Abdallah M., Bashir, Nawaz Haider, Tibpromma, Saowaluck & Dossa, Gbadamassi G. O., 2024, Microfungi associated with dead caterpillars and spiders in Xishuangbanna Tropical Botanical Garden, P. R. China, Phytotaxa 644 (4), pp. 243-257 : 249-250

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

Index Fungorum number: IF265873

Descriptions: Saprobic or entomopathogenic on dead caterpillars, presenting white-brown mycelia surrounding the host. Mycelium 2–6 μm wide (x̄ = 4.5 μm, n = 20), hyaline to dark brown, septate, branched, tubular, thick-walled. The asexual morph produced in the PDA within a month. Sexual morph: undetermined. Asexual morph: Conidiophores developed from hyphae, cylindrical straight to flexuous, thick-walled, sometimes swollen at the base, unbranched, olivaceous brown to dark brown, lighter towards apex. Conidiogenous nodes terminal or intercalary, dark brown, 1–3 μm (x̄ = 2 μm, n = 10). Conidia 20–27 × 7–10 μm (x̄ = 23 × 8.5 μm, n = 20), finely verruculose, straight or curved, ellipsoidal to ovoid, finely verruculose, hyaline to olivaceous to brown, middle cells disproportionately enlarged, apical and basal cells usually paler, 4-distoseptate when fully mature. Hilum protuberant, slightly thickened, 1–3 μm wide. Stroma dark black, branched 50–100 mm high, 1–2 mm wide.

Culture characteristics: The fungal strain sporulated within one month in PDA at 20–25 ℃. Colonies on PDA fast-growing, reaching around 30 cm in one week at room temperature (20–25 ℃). Colonies circular, low convex, lowly dense, brown, edge entire, formed oblong, raised, dark-brown stroma at the peripheries, dark-brown from the reverse. Without pigments produced in PDA media.

Known substratum: Eye infections of human patients ( Nityananda et al. 1964); Microstegium vimineum ( Huang et al. 2017) ; Parthenium hysterophorus ( Priyadharsini & Muthukumar 2017) ; dead caterpillars (this study); Maize ( Manzar et al. 2021); Bletilla striata ( Xie et al. 2023) .

Known distribution: Colombo, Sri Lanka ( Nityananda et al. 1964); Hunan / Yunnan / Zhejiang, China ( Huang et al. 2017, Xie et al. 2023, this study); Tamilnadu / Uttar Pradesh, India ( Priyadharsini & Muthukumar 2017, Manzar et al. 2021).

Material examined: China, Yunnan Province, Xishuangbanna Tropical Botanical Garden, on dead caterpillars, 20 July 2022, Dossa G.G.O., XG9 ( HKAS 129046 ), living culture KUNCC23-13357 .

Notes: Based on the BLASTn searches of LSU, ITS, gapdh, and tef1-α, our isolate KUNCC 23-13357 is highly similar (99–100%) to Curvularia geniculata strains (CBS 187.50, Tea-N8, NB871), meanwhile, the morphological characteristics also well match to the concept of Curvularia and C. geniculata , with developing black, brown stroma on PDA, producing straight or curved, multi-celled conidia, with hila at the base, and the third cell from the base often darker and larger than the others ( Marin-Felix et al. 2020). In addition, the multi-genes phylogenetic analyses also indicated our KUNCC 23-13357 clusters with C. geniculata strains (CBS 187.50, Tea-N8=NB871) ( Figure 1 ). Previously, C. geniculata was often reported as leaf spots causing agent of plant hosts in China, such as Bletilla striata ( Orchidaceae ), Microstegium vimineum , and Musa acuminate ( Huang et al. 2017, Qi et al. 2022, Xie et al. 2023). Thus, here we report a new host record of C. geniculata associated with dead caterpillars ( Figure 3 ).

Figures

FIGURE 1. The Curvularia phylogram was constructed based on combined LSU, ITS, gapdh, and tef1-α sequences. The tree is rooted with Johnalcornia aberrans (CBS 510.91 and CBS 281.91). The BI and ML bootstrap support values equal to or greater than 0.90 BYPP and 60 % are shown at the first and second positions above the nodes, respectively. Type strains are in bold, and newly generated strains are in red.

FIGURE 3. Curvularia geniculata (HKAS 129046). a Mycelia on a dead caterpillar; b,c obverse and reverse in PDA; d–f stromata on PDA; g–j conidiophores, and conidiogenous cells bearing conidia; k–n conidia.