Pestalotiopsis phyllostachydis H.J. Zhao & W. Dong, 2024

Zhao, Haijun, Shu, Yongxin, Doilom, Mingkwan, Zeng, Xiangyu, Zhang, Huang & Dong, Wei, 2024, Pestalotiopsis phyllostachydis sp. nov. from Guangdong, China, Phytotaxa 633 (1), pp. 68-85 : 76

Pestalotiopsis phyllostachydis H.J. Zhao & W. Dong , sp. nov. ( FIGURE 2 )

Index Fungorum number: IF900827; Facesoffungi number: FoF 14613.

Etymology: refers to the host genus Phyllostachys , from which the fungus was isolated.

Holotype: MHZU 23-0119

Endophytic in leaves of Phyllostachys sulphurea . Sexual morph: undetermined. Asexual morph: Conidiomata (on PDA) 400–440 μm diam., acervular, saucer-shaped, aggregated or scattered, semi-immersed, superfical, often exuding black conidial masses. Conidiophores reduced to conidiogenous cells. Conidiogenous cells holoblastic, monoblastic, discrete, subcylindrical, 11–17 × 2–4 μm (x̄ = 14 × 3 μm, n = 10), or ampulliform (6–10 × 1.2–3.8 μm) (x̄ = 8 × 2.5 μm, n = 10), hyaline, smooth. Conidia 18–24 × 5–7 μm (x̄ = 20 × 6 μm, n = 30), fusoid, ellipsoidal, straight to slightly curved, 4-septate, occasionally slightly constricted at septa; basal cell 2.8–4.6 μm long (x̄ = 3.7 μm, n = 30), obconical with a truncate base, hyaline, sometimes with 0–2 short basal appendage 1–7 μm long (x̄ = 4.7 μm, n = 30), tubular, filiform, unbranched or branched, centric; three median cells pale brown to brown, concolorous or sometimes darker at the two upper cells, darker at the septa; apical cell 2.8–5.5 µm long (x̄ = 4.2 μm, n = 30), conical, subcylindrical, hyaline to subhyaline, bearing 2–4 filiform, unbranched tubular apical appendages, 7–26 μm long (x̄ = 17 μm, n = 30).

Culture characteristics: colonies on PDA reaching 77 mm diam. after 10 days at 25 ℃, forming serval circular, floccose to fluffy, white with cottony aerial mycelium on the surface, with smooth edge, producing a few conidiomata exuding black spore masses after a month, white circular, no pigment production in the culture.

Material examined: CHINA, Guangdong Province, Guanghzou City, South China National Botanical Garden, isolated from leaves of Phyllostachys sulphurea (Carrière) Rivière & C. Rivière ( Poaceae ), 17 June 2021, H. J. Zhao, HNZW 177 ( MHZU 23-0119, holotype); ex-type culture ZHKUCC 23-0873.

Notes: in our multi-locus phylogenetic analysis, P. phyllostachydis forms a distinct branch within the genus Pestalotiopsis ( FIGURE 1 ). Pestalotiopsis phyllostachydis exhibits similar morphological characteristics with other species, but it can be distinguished from its relatives by the length of apical appendages. Except for P. thailandica , which has longer apical appendages (5.5–38 μm) as opposed to P. phyllostachydis (7–26 μm), all other species have shorter ones ( TABLE 2). Although P. loeiana has a similar length of apical appendages to P. phyllostachydis , it differs in having longer basal appendages (3–13 μm vs. 2–7 μm) ( Sun et al. 2023). Based on phylogenetic analysis, nucleotide comparison ( TABLE 3), and morphological characteristics, P. phyllostachydis is established as a new species.

Figures

FIGURE 1.—Phylogenetic tree generated from maximum likelihood (ML) analysis based on combined ITS, tef1-α and tub2 sequence data. Bootstrap support values for ML equal to greater than 50%, and posterior probabilities equal to greater than 0.95 are given at the nodes (ML/BYPP). The tree is rooted to Neopestalotiopsis cubana (CBS 600.96) and N. protearum (CBS 114178). The ex-type strains are indicated in bold. The new species is indicated in red.

FIGURE 2 Pestalotiopsis phyllostachydis (MHZU 23-0119, holotype). a, b Cultures on PDA (front and reverse). c Conidiomata on PDA. d–f Conidiogenous cells bearing conidia. g–k Conidia. Scale bars: d–f = 10 µm, g–k = 20 µm.