Beltraniella myristicae W. W. Liu, C. Z. Yin, Z. X. Zhang & X. G. Zhang sp. nov.

Fig. 4

Holotype.

China • Hainan Province, Ledong County, Jianfengling National Forest Park, 18°44'25"N, 108°51'32"E, on diseased leaves of Myristica fragrans (Myristicaceae), 14 October 2023, W. W. Liu, holotype HMAS 352922, ex-type living culture SAUCC 638601.

Etymology.

The epithet “ myristicae ” is derived from the name of the host plant, Myristica fragrans.

Description.

Associated with diseased leaves of Myristica fragrans, the surface of the leaf blade shows black irregular protrusions, marked with black circles and arrows in Fig. 4. Asexual morph: Setae dark-brown, simple, subulate, verrucose, 80.5–99.8 × 2.7–5.5 µm. Conidiophores present two distinct forms: long and short. Long conidiophores emerge from lobed basal cells, macronematous, setiform, upright, straight or gently curved, simple, septate, verrucose, subhyaline to pale olivaceous, swollen at the base, arising from basal cells of setae or from separate, 74.4–150.5 × 2.9–5.3 µm. Short conidiophores hyaline, septate, smooth edges, simple or branched, 18.3–45.0 × 2.7–5.8 µm. Conidiogenous cell polyblastic, ovoid, hyaline, 5.5–12.5 × 2.0–4.9 µm. Separating cells ellipsoid to subglobose, smooth, 7.0–12.8 × 2.5–5.4 µm. Conidia originate directly from the conidiogenous cells in the long conidiophores and from the separating cells in the short ones, aggregated, dry, straight, teardrop-shaped, truncate at distal end, narrow-tipped, terminal, hyaline, smooth, diaphragm, without a hyaline transverse band, 13.6–22.2 × 3.9–9.8 µm. Sexual morph: Inconclusive.

Culture characteristics.

On PDA medium, after seven days of dark incubation in a 25 ° C incubator, colonies reached 68 mm in diameter with a growth rate of 9.2–10.2 mm / day. Colonies on PDA raised, concentric, white, flatter, velutinous edge, with mycelium in the middle portion aggregated into a circle; reverse pale yellow, velutinous edge.

Additional material studied.

China • Hainan Province, Ledong County, Jianfengling National Forest Park, 18°44'25"N, 108°51'32"E, on diseased leaves of Myristica fragrans, 14 October 2023, W. W. Liu, HSAUP 638602, living culture SAUCC 638602.

Notes.

Based on the phylogenetic tree constructed using ITS and LSU sequences, Beltraniella myristicae emerged as the closest to B. brevis DS 2-23 with 94 % MLBS and 1.00 BPP support values (Fig. 1). However, a significant discrepancy was observed in the ITS sequence, with a disparity of 7 / 548 bp between B. myristicae and B. brevis. Morphologically, B. myristicae differed from B. brevis by having shorter setae (B. myristicae: 80.5–99.8 × 2.7–5.5 vs. B. brevis: 89–251 × 4.5–10.5 µm), shorter separating cells (B. myristicae: 7.0–12.8 × 2.5–5.4 vs. B. brevis: 11–18 × 3.4–4.1 µm), and shorter conidia (B. myristicae: 13.6–22.2 × 3.9–9.8 vs. B. brevis: 20–26.5 × 4.5–7.2 µm); differences in conidia (B. brevis: diamond-shaped, with a hyaline supraequatorial transverse band; B. myristicae: teardrop-shaped, without a hyaline transverse band). Consequently, B. myristicae was classified as a new species within the genus Beltraniella, based on a combination of phylogenetic analysis and morphological comparisons