Pseudoplagiostoma quercus Ning Jiang, 2025

Jiang, Ning, Xue, Han & Li, Yong, 2025, Species diversity of Pseudoplagiostoma and Pyrispora (Diaporthales) from Fagaceae hosts in China, IMA Fungus 16, pp. e 153782-e 153782 : e153782-

Pseudoplagiostoma quercus Ning Jiang sp. nov.

Fig. 6

Etymology.

Named after the host genus, Quercus .

Diagnosis.

Distinct from its closely related species of Ps. jianfenglingense by sequence data.

Typus.

CHINA • Henan Province, Xinyang City, Pingqiao District, Haotang Village , on diseased leaves of Quercus aliena , 7 August 2019, Yong Li (holotype CAF 800040 ; ex-type culture CFCC 55232 ) .

Description.

Conidiomata pycnidial, solitary, erumpent, globose to pulvinate, black, 300–700 μm diam., exuding a brown conidial mass. Conidiophores indistinct, often reduced to conidiogenous cells. Conidiogenous cells hyaline, smooth, ampulliform, attenuate towards the apex, phialidic, 10–25 × 2–8.5 μm. Conidia holoblastic, aseptate, hyaline, smooth, thick-walled, multi-guttulate, ellipsoid, oblong-cylindrical, slightly constricted at the middle, slightly curved, base tapering to a flat protruding scar, (16 –) 17–21 (– 21.5) × (8.5 –) 9.5–11 (– 11.5) μm (n = 50), L / W = 1.6–2.3, with a prominent hilum.

Culture characteristics.

Colonies on PDA flat, spreading, with moderate aerial mycelia and smooth margin, white to smoke gray, reaching 80 mm. diam after 2 weeks at 25 ° C, forming black conidiomata with brown conidial masses. Colonies on MEA flat, spreading, with sparse aerial mycelia and smooth margin, forming concentric rings, white to rosy buff, reaching 70 mm diam. after 2 weeks at 25 ° C, sterile. Colonies on SNA flat, spreading, with sparse aerial mycelia and undulating margin, white to isabelline, slowly growing, reaching 70 mm diam. after 3 weeks at 25 ° C, sterile.

Additional materials examined.

CHINA • Henan Province, Xinyang City, Pingqiao District, Haotang Village , on diseased leaves of Quercus aliena , 7 August 2019, Yong Li (culture CFCC 55192 ) ; • Henan Province, Xinyang City, Shihe District, Boerdeng Forest Park , on diseased leaves of Quercus variabilis , 7 August 2019, Yong Li (culture CFCC 55262 ) .

Distribution.

China, Henan Province.

Ecology.

Associated with leaf spot disease of Quercus aliena and Q. variabilis .

Notes.

Three isolates obtained from leaf spots of Quercus aliena and Q. variabilis formed a well-supported clade, described here as Pseudoplagiostoma quercus , which is phylogenetically sister to Ps. jianfenglingense (Fig. 1 ). Morphologically, Ps. quercus and Ps. jianfenglingense exhibit similar conidial shapes and dimensions. However, the two species can be clearly distinguished by sequence divergence, with nucleotide differences of 6 / 551 in ITS, 1 / 796 in LSU, 45 / 536 in TEF- 1 α, and 22 / 471 in TUB 2.

Figures

Figure 1. Phylogram of Pseudoplagiostoma and Pyrispora resulting from a maximum likelihood analysis based on the ITS, LSU, RPB 2, TEF 1 - α and TUB 2 gene loci. Numbers above the branches indicate ML bootstrap values (left, ML BS ≥ 70 %) and Bayesian posterior probabilities (right, BPP ≥ 0.95). Ex-type strains are marked with *.

Figure 6. Morphology of Pseudoplagiostoma quercus (CFCC 55232): A colonies on PDA, MEA and SNA after 10 days at 25 ° C B conidioma formed on PDA C conidiogenous cells giving rise to a conidium D – G conidia. Scale bars: 500 μm (B); 10 μm (C – G).