Phaeobotryon longiparaphysium Y. T. Zhu & Y. M. Liang, 2025

Zhu, Yeting, Liang, Yingmei & Peng, Cheng, 2025, New species and records of Phaeobotryon (Botryosphaeriales, Botryosphaeriaceae) from Larix in China, MycoKeys 112, pp. 1-15 : 1-15

Phaeobotryon longiparaphysium Y. T. Zhu & Y. M. Liang sp. nov.

Fig. 3

Etymology.

Named after the long paraphyses of conidiomata.

Descriptions.

Sexual morph: Not observed. Asexual morph: Conidiomata pycnidial, scattered, immersed or semi-immersed, globose to ovoid, unilocular, 280–550 µm diam. Disc black, 180–330 µm in diam. Ostioles single, central, 65–115 µm. Paraphyses present, hyaline, thin-walled, arising from the conidiogenous layer, extending above the level of developing conidia, tip rounded, aseptate, up to 74.5 × 2.5 µm. Conidiophores reduced to conidiogenous cells. Conidiogenous cells hyaline, smooth, thin-walled, holoblastic, cylindrical, phialidic, proliferating internally with visible periclinal thickening, 9.5–29.0 × 1.0–4.0 µm. Conidia initially hyaline, becoming brown with age, dark brown, thick-walled, oval, with obtuse or gradually acute apex, rounded, gradually acute base, aseptate, 24.0–36.5 × 15.0–20.5 µm (av. ± S. D. = 31.69 ± 2.86 × 18.34 ± 1.01 µm), L / W = 1.7 ± 0.2.

Culture characteristics.

Colonies on PDA with aerial mycelium, thick and fluffy at the edge, margin with undulate and irregular, initially white, gradually turning brown, finally becoming black, covering 40–50 mm after 7 days at 25 ° C.

Materials examined.

China • Hebei Province, Chengde City, Saihanba Forest Farm (42°28'37.08"N, 117°25'45.49"E), alt. 1657 m, on branches of Larix gmelinii var. principis-rupprechtii, 10, Jul. 2023, C. M. Tian, C. Peng, S. J. Li, Y. Yuan, M. W. Zhang (holotype BJFC -S 2372 , ex-holotype cultures CFCC 70807 , CFCC 70808 ) . China • Jilin Province, Yanbian Korean Autonomous Prefecture, Yanji City, Maoershan National Forest (42°51'12.96"N, 129°28'24.06"E), alt. 297 m, on branches of Larix olgensis , 7, Sept, 2022, C. Peng, X. Y. Zhang ( BJFC -S 2373 , living culture CFCC 70809 ) .

Notes.

Phaeobotryon longiparaphysium formed a distinct clade (MP / ML / BI = 97 / 99 / 1) in the multi-locus analyses and is sister to P. laricinum (Fig. 1 ). These two species can be distinguished based on the ITS, LSU, and tef 1 - α loci, with P. longiparaphysium exhibiting 29 bp differences from P. laricinum (5 / 535 in ITS, 5 / 780 in LSU, and 19 / 291 in tef 1 - α). Furthermore, P. longiparaphysium (L / W = 1.7 ± 0.2) can be distinguished from P. laricinum (L / W = 2.3 ± 0.3) by its smaller conidial L / W ratio (Table 3 ).

Figures

Figure 1. Phylogenetic tree inferred from ML analysis based on combined ITS, LSU, and tef 1 - α sequence data of Phaeobotryon isolates. The tree was rooted in Lasiodiplodia theobromae (CBS 164.96). The MP, ML (≥ 50 %), and BI (≥ 0.9) bootstrap values are given at nodes (MP / ML / BI). Isolates from this study are marked in blue, ex-type strains are marked in bold, and new species are in a colored font.

Figure 3. Phaeobotryon longiparaphysium (BJFC - S 2372) A habit of conidiomata on twig B, E longitudinal section through a conidioma C, F transverse section of a conidioma D, G – J conidiogenous cells and conidia K conidia L colony on PDA after 14 days. Scale bars: 500 µm (A – C); 50 µm (E, F); 10 µm (D, G – K).