Phyllosticta capitalensis Henn., Hedwigia 48: 13. 1908

Zhang, Zhaoxue, Liu, Xiaoyong, Zhang, Xiuguo & Meng, Zhe, 2022, Morphological and phylogenetic analyses reveal two new species and a new record of Phyllosticta (Botryosphaeriales, Phyllostictaceae) from Hainan, China, MycoKeys 91, pp. 1-23 : 1

Phyllosticta capitalensis Henn., Hedwigia 48: 13. 1908

Fig. 4

Description.

Leaf endogenic and associated with leaf spots. Asexual morph: Conidiomata pycnidial, mostly aggregated in clusters, black, erumpent. In MEA, cultures exuded colourless to opaque conidial masses, appeared on pycnidia after 10 days or longer. Pycnidial walls of multilayered, textura angularis, brown to dark brown, up to 35 μm thick; inner walls hyaline. Conidiophores subcylindrical to ampulliform, frequently reduced to conidiogenous cells or branching from a basal supporting cell, coated in mucoid layer, 8.0-14.0 × 3.0-5.0 μm. Conidiogenous cells terminal, subcylindrical to ampulliform, hyaline, smooth, 8.0-11.0 × 3.0-4.5 μm. Conidia 9.0-12.5 × 5.0-7.0 μm, mean ± SD = 10.6 ± 0.9 × 6.2 ± 0.5 μm, solitary, hyaline, aseptate, thin and smooth walled, coarsely guttulate or with a single large central guttule, ovoid, ampulliform, ellipsoidal to subglobose, enclosed in a thin mucoid sheath, 1.3-2.7 μm thick and bearing a hyaline, apical mucoid appendage, 3.0-8.5 × 1.0-1.5 μm, flexible, unbranched, tapering towards an acutely rounded tip. Spermatia hyaline, smooth, guttulate to granular, bacilliform, 6.0-8.2 × 1.3-2.0 μm, occurring in conidioma with conidia. Sexual morph: Ascomata shape and wall like those of the conidiomata. Asci bitunicate, hyaline, clavate to broadly fusoid-ellipsoid, with visible apical chamber, 2 μm diam., 45-85 × 9-13 μm. Ascospores bi- to multiseriate, hyaline, smooth, granular to guttulate, aseptate, straight, rarely curved, widest in the middle, limoniform with obtuse ends, 15-18 × 6-7 μm.

Culture characteristics.

Colonies on PDA occupying an entire 90 mm Petri dish in 14 days at 25 °C in darkness, with a growth rate of 6.0-6.5 mm/day, greenish-black in obverse and reverse. Colonies on MEA 82-86 mm in diameter after 14 days at 25 °C in darkness, with a growth rate of 5.7-6.2 mm/day, undulate at edge, white to grey white in obverse and reverse, with moderate aerial mycelia on the surface, with black, gregarious conidiomata.

Specimens examined.

China, Hainan Province: Bawangling National Forest Park, on diseased leaves of Rhapis excelsa (Thunb.) Henry ex Rehd , 19 May 2021, Z.X. Zhang, HSAUP210144, living culture SAUCC210144; on diseased leaves of Rhapis excelsa . 19 May 2021, Z.X. Zhang, HSAUP210148, living culture SAUCC210148 .

Notes.

Based on morphological features, Hennings (1908) described Phyllosticta capitalensis and Glienke et al. (2011) added molecular data. The holotype (CBS 128856) of P. capitalensis was collected from Stanhopea graveolens ( Glienke et al. 2011). In our current study, two isolates (SAUCC210144, SAUCC210148), collected from diseased leaves of Rhapis excelsa , cluster in the P. capitalensis clade (Fig. 1 ). Although four other species are also in this clade, we consider these two isolates as P. capitalensis , based on their morphological characters, such as granular to guttulate ascospores (15-18 × 6-7 vs. 15-17 × 5-6 μm), subcylindrical to ampullate conidiogenous cells (8.0-11.0 × 3.0-4.5 vs. 7-10 × 3-5 μm), ellipsoidal to subglobose conidia (9-12.5 × 5-7 vs. 11-12 × 6-7 μm) and hyaline, apical mucoid appendages (3-8.5 × 1-1.5 vs. 6-8 × 1-1.5 μm).

Figures

Figure 1. Phylogram of the Phyllosticta capitalensis species complex, based on a concatenated ITS, LSU, tef 1, ACT and GPDH sequence alignment, with Phyllosticta hubeiensis (CGMCC 3.14986, CGMCC 3.14987) of the P. cruenta species complex serving as outgroup. Bayesian Inference posterior probabilities and Maximum Likelihood bootstrap support values above 0.70 and 70 % are shown at the first and second position, respectively. Ex-type cultures are indicated in bold face. Strains obtained in the current study are in red. Some branches are shortened for layout purposes - these are indicated by two diagonal lines with the number of times. The bar at the left-bottom represents substitutions per site.

Figure 4. Phyllosticta capitalensis (holotype SAUCC 210144) a diseased leaf of Rhapis excelsa b, c colonies (left-above, right-reverse) after 15 days on PDA (b) and MEA (c) d conidiomata e asci and ascospores f asci, ascospores and conidia g conidiogenous cells with conidia h conidia i spermatia. Scale bars: 10 μm (e-i).