Pseudopestalotiopsis celtidis Qi Yang & Yong Wang

Yang, Qi, He, Yu-Ke, Yuan, Jun & Wang, Yong, 2022, Two new Pseudopestalotiopsis species isolated from Celtis sinensis and Indocalamus tessellatus plants in southern China, Phytotaxa 543 (5), pp. 274-282 : 278

Pseudopestalotiopsis celtidis Qi Yang & Yong Wang bis, sp. nov. ( Fig. 2 )

MycoBank: MB 842468

Index Fungorum: IF 559463

Etymology. celtidis refers to the host plant ( Celtis sinensis ) from which the fungus was isolated.

Type. China, Yunnan Province, Xishuangbanna Prefecture , from leaves of Celtis sinensis , 20 June 2018, J. Yuan, HGUP 538 , holotype, ex-type living culture GUCC 21599 .

Disease symptom: Pathogenic, causing spots on leaves of Celtis sinensis . Leaf spots irregular to circular in shape, brown, 7–12 mm diam., slightly sunken, scattered. Small auburn spots appear initially and then gradually enlarge, changing to off-white circular ring spots with a dark mahogany border and jagged edge.

Description: Asexual morph: Colonies on PDA reaching 7–8.5 cm diam. after 7 d at room temperature (28 ˚C), under 12 hours of light-dark alternation. Mycelium light pink to off-white, filamentous, circular, slightly undulate at edge, whitish, with black clustered fruiting bodies, filiform and fluffy margin, white from above and light yellow from reverse. Conidiomata pycnidial, 100–600 µm in diam., globose, solitary, black, semi-immersed on PDA, exuding brown to dark brown mass of conidia. Conidiophores branched or unbranched, hyaline or light brown, thin-walled. Conidiogenous cells discrete, ampuliform to lageniform, hyaline, thin-walled, smooth. Conidia fusiform to clavate, straight to slightly curved, 4-septate, 21.5–29.5 × 6.5–9 (x = 25.4 × 7.4 µm), basal cell cylindrical to obconic, hyaline or sometimes pale brown, thin-walled, smooth, 2.5–5.5 µm (x = 3.7 µm), the three median cells 14–20 µm (x = 17.6 µm), concolourous, dark brown with darker septa, second cell from base 5–8 µm (x = 6.4 µm), third cell 3.5–6.5 µm (x = 4.9 µm), fourth cell 4.5–7 µm (x = 5.8 µm), apical cell 2–4.5 µm (x = 3.3 µm), cylindrical to sub-cylindrical, hyaline, with 1–3 (mostly 2) tubular apical appendages, arising from the apex of the apical cell each at different points, flexuous, 8–18 µm (x = 12.4 µm) long, basal appendage often present, single, tubular, unbranched (or rarely branched), short, 1.5–4 µm (x = 2.8 µm) long. Sexual morph: undetermined.

Notes: The phylogenetic tree supported GUCC 21599 as sister to P. annellata (NTUCC 17-030 T) with high support ( Fig. 1 ). Comparing the two strains there were 11 base pai differences in ITS, one character difference in tub2, and eight characters differences in tef1 ( TABLE 2 ). In morphology, Pseudopestalotiopsis celtidis was morphologically similar to P. annellata . However, P. annellata can be distinguished by the different number of apical appendages (2–3), longer apical appendages ((18–)22–32(–35) µm) and longer basal appendages ((4–)5–7(–8) µm) ( Tsai et al. 2021). Thus, P. celtidis is introduced as a new species.

Figures

FIGURE 1. Maximum parsimony (MP) tree of Pseudopestalotiopsis based on combined datasets of ITS, tub2 and tef1 sequences. MP and maximum likelihood bootstrap values ≥50%, Bayesian posterior probabilities ≥0.90 (MPBS/MLBS/PPBY) are given below and above the nodes. Our strains in this study are in red. Ex-type strains are marked by T.

FIGURE 2. Pseudopestalotiopsis celtidis (GUCC 21599). a, b. Leaf spots on Celtis sinensis. c, d. Culture on PDA (d-above, e-reverse). e. Colony sporulating on PDA. f–g. Conidia and conidiophores. h–l. Conidia. Scale bars: e = 1000 µm, f–l = 20 µm.