Dothidea kunmingensis Y. Gao, Gentekaki E & Monkai, 2021

Gao, Ying, Monkai, Jutamart, Gentekaki, Eleni, Ren, Guang-Cong, Wanasinghe, Dhanushka N., Xu, Jian-Chu & Gui, Heng, 2021, Dothidea kunmingensis, a novel asexual species of Dothideaceae on Jasminum nudiflorum (winter jasmine) from Southwestern China, Phytotaxa 529 (1), pp. 43-56 : 50

Dothidea kunmingensis Y. Gao, Gentekaki E & Monkai , sp. nov.

Index Fungorum number: IF558766; Facesoffungi numbers: FoF 09911; FIGURE 2

Etymology: Named after the location, Kunming from where the holotype was collected.

Holotype: HKAS 112234

Saprobic on dead twigs of Jasminum nudiflorum (Oleaceae) . Sexual morph: Undetermined. Asexual morph: coelomycetous. Conidiomata 70–115 × 41–74 µm (x̅ = 89 × 57 μm, n = 10), pycnidial, solitary, immersed, globose to subglobose, dark brown to black, unilocular, without an ostiole. Conidiomata wall 10–15 µm thick, 2–3 layered, comprising dark brown to black cells of textura angularis to textura globosa. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 5–6 × 4–5 µm (x̅ = 5.4 × 4.4 µm, n = 25), enteroblastic, phialidic, single, discrete, determinate, doliiform to ampulliform or subcylindrical, hyaline, arising from conidiomata wall. Conidia 8.5–12.5 × 8–12 µm (x̅ = 9.9 × 9.3 µm, n = 25), one-celled, subglobose to ovoid, hyaline to pale-brown, smooth, thick-walled.

Culture characteristics: Conidia germinating on PDA within 24 h and germ tubes developing from both ends. Colonies on PDA reaching 22 mm in 2 weeks at 25–27 °C, gelatinous, circular, with irregular edge, white to pale yellow from above and reverse, becoming dark in the center after one week. Mycelium superficial to immersed in media, with branched, septate, smooth, hyphae, releasing conidia in a pale brown, slimy, globose, glistening mass. Sporulated after two weeks. Conidiomata, pycnidial, globose, brown, semi-immersed on PDA. Conidiogenous cells 4.7–6.4 × 3.9–4.8 µm (x̅ = 5.5 × 4.6 µm, n = 25), enteroblastic, phialidic, discrete, ampulliform to doliiform, hyaline, smooth-walled, arising from basal stratum. Conidia 4.2–5.1× 2.6–3.5 µm (x̅ = 4.7 × 3.2 µm, n = 25), one-celled, subglobose, ovoid to ellipsoid, hyaline to pale brown, guttulate, smooth, thick-walled.

Material examined: CHINA, Yunnan Province, Kunming Botanical Garden , (25°8.19'N, 102°44.25'E), dead twigs of Jasminum nudiflorum Lindl. , 24 August 2020, Ying Gao (HKAS 112234, holotype), ex-type living culture, KUMCC 21-0083 .

Note: Phylogeny of a concatenated SSU-LSU-ITS- tub 2- tef 1-α sequence dataset depicts Dothidea kunmingensis as a sister taxon of D. eucalypti with 70 % ML and 1.00 PP statistical support ( Fig. 1 ). Dothidea eucalypti was introduced by Crous et al. (2017b) and isolated from the leaves of Eucalyptus dalrympleana (Myrtaceae) in New South Wales, Australia. Morphologically, Dothidea kunmingensis has comparatively shorter conidia (4.2–5.1 µm) to those of D. eucalypti (7–12 µm; Crous et al. 2017b). Furthermore, the conidia of Dothidea kunmingensis are subglobose to ellipsoid and pale-brown, whereas D. eucalypti has subcylindrical and hyaline conidia ( Crous et al. 2017b). Dothidea kunmingensis differs from D. eucalypti in 28/494 bp of ITS (5.7 %, without gaps) and 10/910 bp of LSU (1.1 %, without gaps) confirming that the two are different species (Jeewon & Hyde 2016).

Figures

FIGURE 1. Phylogenetic tree obtained inferred from 69 taxa and 4287 sites of a combined SSU, LSU, ITS, tub2 and tef1-α sequence dataset. Numerical values at the nodes indicate maximum likelihood bootstrap support (MLBS) and posterior probabilities (PP) in this order.Bootstrap support values for ML higher than 70 % and PP higher than 0.95 are indicated at the node. Ex-type strains are in bold font; the newly generated sequence is in blue bold font.

FIGURE 2. Dothidea kunmingensis (KUMCC 21-0083 holotype) on decaying stem of Jasminum nudiflorum (a‒k) and on PDA after 4 weeks (1‒x). a, b. Conidiomata on a decaying stem of Jasminum nudiflorum. c. Vertical sections through conidioma.d. Conidioma wall. e, f, o, p. Conidiogenous cells and developing conidia. g–j, r–x. Conidia. k. Germinating conidia. l–m. Culture characteristics on PDA after 2 weeks (l = from above, m = from below). n. Conidiomata on PDA after 4 weeks. q. Conidiogenous cell and conidiophore. Scale bars: c = 30 µm, d = 10 µm, e = 5 µm, f = 10 µm, g–j = 5 µm, k = 20 µm, o = 5 µm, p–r = 10 µm, s–x = 2 µm.