Neopestalotiopsis theobromicola
Neopestalotiopsis theobromicola Fallahi, Jayaward. & K.D. Hyde, in Fallahi, Armand, Al-Otibi, Hyde & Jayawardena, MycoKeys 117: 244 (2025)
Index Fungorum number: IF903267 Facesoffungi number:
Associated with leaf spots of cacao (Theobroma cacao). Sexual morph not observed. Conidiomata acervularon on PDA, aggregated and scattered, immersed and semi-immersed in agar medium, exuding black conidial mass. Conidiophores reduced to conidiogenous cells. Conidiogenous cells hyaline to pale brown, subcylindrical to ampuliform, 3–7 × 2–5 μm. Conidia clavate or fusiform, straight or slightly curved, yellow-brown to brown, 4 septate, 20–30 × 5–7.5 μm (mean = 26 × 6.5 μm, n = 30). Basal cell hyaline, conoid, with truncate base, 3.5–8 μm long; median cells, versicolored, darker than other cells, 14–19 μm long (mean = 17 μm, n = 30) (second cell from the base yellow-brown, 4–6.8 μm long; third cell from the base medium brown, 4.6–7 μm long; fourth cell from the base pale to medium brown, 4–7 μm long); apical cell hyaline, conic, 3–6 μm with 2–3 tubular apical appendages, hyaline, filiform, unbranched, and 15–29 μm long (mean = 22.5 μm, n = 30); basal appendage tubular, unbranched, solitary, hyaline, and 2–5.5 μm long.
Culture characteristics: Colonies on PDA reach 65–70 mm in diameter after seven days of growth at 25 °C under 12 h daylight, white with moderate aerial mycelium, shape irregular, edge undulated, margin fluffy, with black conidial mass. The upper view is white, reverse honey-colored with age.
Material examined: Thailand, Chiang Rai Province, Phan District, Sai Khao, on leaf spots in cacao (Theobroma cacao), February 2023, Maryam Fallahi, dried culture MF115-1 (MFLU 24-0258, holotype), ex-holotype culture MFLUCC 24-0253.
Notes: Strain MFLUCC 24-0253 formed an independent branch in the subclade, including the strains and ex-type strains of Neopestalotiopsis acrostichi and N. guajavicola with 75% ML bootstrap support and 0.94 BYPP, and is introduced here as a new species, namely Neopestalotiopsis theobromicola. The base pair differences between N. theobromicola strains MFLUCC 24-0253 (holotype) and MFLUCC 17-1754 (ex-type) revealed a 0.40% nucleotide difference in ITS (2/504 bp, 3 gaps) and no difference in tef1 and tub2. The base pair differences between N. theobromicola (ex-type strain MFLUCC 24-0253) and ex-type strains of N. guajavicola (FMBO 129) revealed a 0.20% nucleotide difference in ITS (1/506 bp), 0.26% differences in tef1 (1/426 bp), and 0.25% differences in tub2 (1/396 bp). Neopestalotiopsis theobromicola (ex-type strain MFLUCC 24-0253) differs from the type strain of N. acrostichi by having the conidia with 2-3 apical appendages (N. acrostichi: conidia with 3-5 apical tubular appendages, (16–)19–28. 5(–33. 5) μm long) (Norphanphoun et al. 2019). Neopestalotiopsis theobromicola (MFLUCC 24-0253) differs from the type strain of N. guajavicola by having larger conidia with an L/W ratio = 4 (26 × 6.5 μm in N. theobromicola (ex-type strain MFLUCC 24-0253) vs. 23.3 ± 1.6 × 6.5 ± 0.5 μm in N. guajavicola (FMBO 129)) (UI Haq et al. 2021).
Figure 1. Neopestalotiopsis theobromicola (MFLUCC 24-0253, holotype) a leaf spots in cacao b front, and c back views of the colony on PDA after 30 days at 25 °C d conidiomata on SNA e–i conidiophore and conidiogenous cells j–n conidia. Scale bars: 20 μm.
References
Recent Genus
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Halorosellinia
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Neopestalotiopsis theobromicola