Pestalotiopsis manyueyuanani S.Y. Hsu, Y.C. Xu, W.Y. Chuang & Ariyawansa, 2024

Hsu, Sheng-Yu, Xu, Yuan-Cheng, Lin, Yu-Chen, Chuang, Wei-Yu, Lin, Shiou-Ruei, Stadler, Marc, Tangthirasunun, Narumon, Cheewangkoon, Ratchadawan, AL-Shwaiman, Hind A., Elgorban, Abdallah M. & Ariyawansa, Hiran A., 2024, Hidden diversity of Pestalotiopsis and Neopestalotiopsis (Amphisphaeriales, Sporocadaceae) species allied with the stromata of entomopathogenic fungi in Taiwan, MycoKeys 101, pp. 275-312 : 275

Pestalotiopsis manyueyuanani S.Y. Hsu, Y.C. Xu, W.Y. Chuang & Ariyawansa sp. nov.

Fig. 6

Etymology.

The specific epithet ' manyueyuanani ' is based on the place the fungus was originally collected.

Typification.

Taiwan, New Taipei City, Manyueyuan National Forest Recreation Area, on stroma of Ophiocordyceps sp. parasitic on an insect ( Cletus sp., Hemiptera ), 25 May 2018, Wei-Yu Chuang, holotype, NTUPPMH 18-165 (permanently preserved in a metabolically inactive state), ex-holotype NTUPPMCC 18-165 (= CD07). ibid., ex-isotype NTUPPMCC 22-012.

Description.

Based on the morphology of ex-holotype 18-165 growing on carnation leaves ( Dianthus caryophyllus ) supplanted on WA. Sexual morph was not observed on culture. Asexual morph: Conidiomata acervular, globose, scattered, solitary, semi-immersed, black, <30-100 μm diam.; oozing globose to subcylindrical, black conidial masses. Conidiophores pyriform to subcylindrical, hyaline, smooth, indistinct and frequently merged to conidiogenous cells. Conidiogenous cells ampulliform to spherical, hyaline, smooth, (2.8-)3.8-5.3(-6.0) × (6.8-)8.2-12.4(-14.7) μm, x- ± SD = 4.6 ± 0.7 × 10.3 ± 2.1 μm. Conidia fusoid, straight or slightly curved, 4-septate, smooth, slightly constricted at the septa, (6.7-)7.4-9.2(-10.4) × (22.5-)24.6-30.0(-32.7) μm, x- ± SD = 8.3 ± 0.9 × 27.3 ± 2.7 μm, bearing appendages; basal cell obconic with a truncate base, hyaline or pale brown, thin-walled, (2.9-)3.5-4.7(-5.3) μm long, x- ± SD = 4.1 ± 0.6 μm; three median cells doliiform to subcylindrical, pale brown to brown, concolourous, thick-walled, the first median cell from base (5.3-)5.8-7.9(-9.2) μm long (x- ± SD = 6.9 ± 1.0 μm), the second median cell (4.1-)4.9-6.6(-7.8) μm long (x- ± SD = 5.7 ± 0.9 μm), the third median cell (4.3-)5.5-7.3(-8.6) μm long (x- ± SD = 6.4 ± 0.9 μm), together (15.1-)16.7-21.2 (-24.5) μm long (x- ± SD = 18.9 ± 2.3 μm); apical cell conical with an acute apex, hyaline, thick-walled, (2.2-)3.3-5.1(-5.8) μm long (x- ± SD = 4.2 ± 0.9 μm). Appendages tubular, hyaline, unbranched, straight or slightly bent, apical appendage single (rarely two), (3.9-)8.7-16.8(-19.1) μm long (x- ± SD = 12.8 ± 4.0 μm), lateral appendages 1-4 (mostly 2, occasionally absent), forming from apical cell, arising above the septum dividing the apical cell and the third median cell, (5.4-)7.3-13.4(-15.4) μm long (x- ± SD = 10.3 ± 3.0 μm), basal appendage single (occasionally absent), centric, (1.8-)2.7-5.5(-6.5) μm long (x- ± SD = 4.1 ± 1.4 μm). Germinating conidia pattern, solitary or multiple, forming from inflated apical cell or median cells.

Culture characteristics.

Colonies on PDA reaching 18-24 mm diam. after culturing at 25 °C in the dark for seven days, circular, flat with entire to slightly undulate edge, aerial mycelium sparse, yellowish to orange in the centre, whitish at the margin; reverse similar in colour.

Notes.

Pestalotiopsis manyueyuanani sp. nov. is a representative of Pestalotiopsis in having pale brown to brown, concolourous median cells without knobbed apical appendages. In both single and concatenated gene analysis, two isolates of P. manyueyuanani clustered in a distinct clade with strong statistical support basal to the clade comprising P. castanopsidis CFCC 54384 and CFCC 54430, P. cyclobalanopsidis CFCC 54328, P. guizhouensis CFCC 54803, P. jesteri CBS 109350 and P. montellica MFLUCC 12-0279 (Fig. 2 and Suppl. material 2: figs S5-S7). However, P. manyueyuanani has overlapping conidial morphologies with P. castanopsidis , P. cyclobalanopsidis , P. eleutherococci , P. guizhouensis , P. jesteri , P. lijiangensis and P. montellica , showing that these taxa are cryptic species as shown in Suppl. material 1: table S8. At present, the species limitations of cryptic taxa are widely determined by phylogenies, based on single/multi-locus sequence data together with ecology (including host range and pathogenicity), distribution or physiology ( Crous et al. 2015; Tsai et al. 2018). Apart from the unique placement in phylogenetic inference, P. manyueyuanani differs from other taxa clustered as mentioned above, by host and distribution (Suppl. material 1: table S2). In addition, to further support our hypothesis, we also implemented PHI tests to determine if there are any occurrences of sexual recombination between P. manyueyuanani and its closely-related taxa ( P. castanopsidis , P. cyclobalanopsidis , P. eleutherococci , P. guizhouensis , P. jesteri , P. lijiangensis and P. montellica ). The PHI tests indicated that there were no significant recombinations detected within tested groups (Fig. 7 , ITS: Фw = 0.5665; tub2: Фw = 0.7653; tef1-α: Фw = 0.6276), supporting reproductive isolation within the phylogenetically closely-related groups. Therefore, based on these observations, we introduce P. manyueyuanani (NTUPPMCC 18-165 and NTUPPMCC 22-012) as a novel species in the genus Pestalotiopsis .

Figures

Figure 2. ML phylogenetic tree of Pestalotiopsis obtained from the concatenated DNA sequence data of ITS, tub 2 and tef 1 - α genes implemented in IQ-TREE. ML bootstrap values (MLB) ≥ 70 %, Maximum Parsimony bootstrap (MPB) values ≥ 70 % and Bayesian Posterior Probabilities (PP) ≥ 0.95 are given at the nodes. The scale-bar shows the number of estimated substitutions per site. Neopestalotiopsis protearum (CBS 114178) was used as an outgroup. The new isolates are in red and taxa representing ex-type cultures are in bold.

Figure 6. The morphology of Pestalotiopsis manyueyuanani A the original habitat of conidia of Pestalotiopsis manyueyuanani; stroma of Ophiocordyceps sp. B top view (left) and bottom view (right) of the colony on potato dextrose agar (PDA) after incubation for seven days C formation of conidiomata on carnation leaf D, E conidiogenous cells and immature conidia F-K conidia L-N germinated conidia. Scale bars: 250 μm (C); 10 μm (D-K); 20 μm (L-N).

Figure 7. Split graphs showing the results of PHI tests for three gene regions (A ITS B tub 2 C tef 1 - α) of Pestalotiopsis manyueyuanani with their phylogenetically closely - related species using LogDet transformation and splits decomposition options. The new taxon in each graph is shown in red and taxa representing ex-type strains are in bold.