Neopestalotiopsis theobromicola Fallahi, Jayawar. & K. D. Hyde sp. nov.

Fig. 31

Etymology.

‘ theobromicola ’ refers to the host plant genus from which the fungus was isolated.

Description.

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 MF 115-1 (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 (Fig. 28), 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 tef 1 and tub 2. 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 tef 1 (1 / 426 bp), and 0.25 % differences in tub 2 (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).