Cytospora spiraeae Fan, 2018

Zhu, Hai-Yan, Tian, Cheng-Ming & Fan, Xin-Lei, 2018, Multigene phylogeny and morphology reveal Cytospora spiraeae sp. nov. (Diaporthales, Ascomycota) in China, Phytotaxa 338 (1), pp. 49-62 : 57-59

Cytospora spiraeae Fan sp. nov. Fig. 3

MycoBank MB 823824

Holotype:— China, Gansu Province, Gannan City , 34°17'22.16"N, 102°58'44.23"E, from branches of Spiraea salicifolia, Aug. 2012 , X. L. Fan, deposited by X. L. Fan, holotype BJFC-S784 , ex-type living culture CFCC 50049 .

Etymology:—Named after the host genus on which it was collected, Spiraea .

Descriptions:— Ascostromata immersed in the bark, erumpent through the surface of bark in a large area, scattered, (920–)950–1100(–1240) μm in diam., with 5–8 perithecia arranged circularly or irregularly. Conceptacle absent. Ectostromatic disc dark grey to black, usually surrounded by tightly ostiolar necks, triangular to circular, (240–)280–340(–390) μm in diam., with 5–8 ostioles arranged circularly per disc. Ostioles numerous, dark brown to black, at the same or above level as the disc, concentrated, arranged triangularly to circularly in a disc, (50–)52.5–80(–98) μm in diam. Perithecia dark grey to black, flask-shaped to spherical, arranged circularly, (250–)270–400(–440) μm in diam. Asci free, clavate to elongate obovoid, (25.5–)27–35(–37) × (5–)6.5–8(–9.5) μm, 8-spored. Ascospores biseriate, elongate-allantoid, thin-walled, hyaline, aseptate, (6–)7–8(–8.5) × (1.5–)2–2.5 μm. Pycnidial stromata ostiolated, immersed in bark, scattered, erumpent slightly through the surface of bark, with multiple locules. Conceptacle absent. Ectostromatic disc dark brown, unconspicuous, circular, (200–)225–290(–325) μm in diam., with 1–4 ostioles per disc. Ostioles black, unconspicuous, at the same level as the disc surface, arranged circularly in a disc, (40–)45–70(–85) μm in diam. Locule numerous, subdivided frequently by invaginations with common walls, (980–)1050–1250(–1320) μm in diam. Conidiophores hyaline, branched at base or not branched, thin walled, filamentous. Conidiogenous cells enteroblastic polyphialidic. Conidia hyaline, allantoid, smooth, aseptate, thin-wall, (5–)5.5–6.5(–7) × (1–)1.5 μm.

Culture characteristics: Culture on PDA is initially white, becoming fawn after 7–10 days. The colony is flat, felt-like, thin with a uniform texture, lacking aerial mycelium. Pycnidia distributed irregularly on medium surface.

Materials examined: — China, Gansu Province, Gannan City , 34°17'22.16"N, 102°58'44.23"E, from branches of Spiraea salicifolia, Aug. 2012 , X. L. Fan, deposited by X. L. Fan, BJFC-S785 , living culture CFCC 50050 ; Shanxi Province, Datong City, Wenying Lake Park, 40°04'32.02"N, 113°22'13.17"E, from branches of Spiraea salicifolia, Apr. 2014 , X. L. Fan, deposited by X. L. Fan, BJFC-S1058 , living culture CFCC 50051 .

Notes:— Cytospora spiraeae is associated with canker disease of Spiraea salicifolia . Morphologically, this species possesses obviously multiple ostioles and locules with common walls, which is similar with Cytospora carbonacea and Cytospora schulzeri , species but the host. Cytospora spiraeae has smaller locules with a centre column as compared with C. schulzeri (950–1100 vs. 1400–1500 μm) in diam., and it has smaller conidia than C. carbonacea (5.5–6.5 × 1.5 vs. 9–13 × 2–3 μm) (Fotouhifar et al. 2007; Zhang et al. 2014; Yang et al. 2015). The clear phylogenetic distinction with all other available strains included in this study, resulted in this species represented an individual clade. Cytospora spiraeae represented the unique Cytospora isolated from Spiraea salicifolia in China. Thus the current study indicated is as a new species and provides the clear phylogenetic distinction with all other available strains and holomorphic descriptions.

Figures

FIGURE 3. Morphology of Cytospora spiraeae from Spiraea salicifolia (BJFC-S784). A: Habit of ascomata on twig. B: Transverse section of ascomata. C: Longitudinal section through ascomata. D: Habit of conidiomata on twig. E: Transverse section of conidiomata. F: Longitudinal section through conidiomata. G–H: Asci. I: Ascospores. J–K: Conidiophores and Conidiogenous cells. L: Conidia. M: Colonies on PDA at 3 days (left) and 30 days (right). Scale bars: B–C, E–F = 500 μm; G–L = 10 μm.