Dothiorella albiziae Rathnayaka & K.D. Hyde, 2022

Rathnayaka, Achala R., Chethana, K. W. Thilini, Phillips, Alan J. L. & Jones, E. B. Gareth, 2022, Two new species of Botryosphaeriaceae (Botryosphaeriales) and new host / geographical records, Phytotaxa 564 (1), pp. 8-38 : 19

Dothiorella albiziae Rathnayaka & K.D. Hyde , sp. nov.

Index Fungorum number: IF559720; Facesoffungi number: FoF 11669; Fig. 6 .

Etymology:—In reference to Albizia lebbeck , the host from which the fungus was collected.

Holotype:— MFLU 22-0093

Saprobic on dead Albizia lebbeck dry pod. Sexual morph: Undetermined. Asexual morph: Coelomycetous. Conidiomata 310–340 μm high × 250–265 μm diam. (x̄ = 320 × 262 μm, n = 10), pycnidial, solitary or gregarious, globose, formed in uniloculate stromata, immersed, becoming erumpent at maturity. Conidiomata wall 24–68 μm diam., of two layers, outer layer composed of thick-walled, dark brown to brown cells of textura angularis, inner layer composed of thin-walled, pale brown to hyaline cells of textura angularis. Conidiophores usually reduced to conidiogenous cells. Conidiogenous cells 5–10 × 2–5 μm (x̄ = 7.5 × 3 μm, n = 20), lining the pycnidial cavity, holoblastic, hyaline, cylindrical, discrete, determinate, smooth-walled. Conidia 14–18 × 6–8 μm (x̄ = 16 × 7 μm, n = 20), oblong to ovoid, straight, rounded at both ends, initially hyaline and aseptate becoming brown and 1-septate often while attached to conidiogenous cell, guttulate.

Culture characteristics: — Conidia germinating on PDA within 24 h. Germ tubes produced from one side of the conidium. Colonies on PDA reaching 1.0– 1.5 cm diam. after 10 days at 25 °C, circular, dense, convex with papillate surface, black colour in both upper and lower sides.

Material examined:— THAILAND. Phayao: on dead dry pod of Albizia lebbeck (Fabaceae) , 20 July 2020, Achala Rathnayaka (MFLU 22-0093, holotype); ex-type living culture MFLUCC 22-0057.

Notes:—In the multi-gene phylogeny (ITS, LSU, tef 1-α and β-tub), our novel strain (MFLU 22-0093/ MFLUCC 22-0057) formed a separate lineage sister to D. thailandica with 81% ML bootstrap and 0.76 PP support ( Fig. 1 ). Although the conidia of D. albiziae (16 × 7 μm) and D. thailandica (18.5 × 7 μm) are of similar size, there are several differences in conidial morphology between these two species ( Phillips et al. 2013). Conidia in D. thailandica are oblong to ellipsoidal, slightly constricted at the septa, with slight undulating striations on the surface, occasionally curved and the lower cell is smaller than the upper cell ( Phillips et al. 2013). In D. albiziae , the conidia are oblong to ovoid, not constricted at the septa, and the upper and lower cells are of similar size. Base pair differences (without gaps) between D. albiziae and D. thailandica are: ITS = 1.8% (8/455), LSU = 0.3% (2/794), tef 1-α = 3.7% (9/242) and β-tub = 2.1% (7/341). Considering the morpho-molecular data analysis, we established D. albiziae as a new species.

Figures

FIGURE 1. Phylogram generated from ML analysis based on combined dataset of ITS, LSU, tef1-α and β-tub. The tree is rooted to Neofusicoccum luteum (CMW 4165 and CBS 562.26). Tree topology is similar to the previous study by Zhang et al. (2021). Bootstrap support values for ML ≥ 70% and Bayesian posterior probabilities (PP) ≥ 0.90 are noted at the nodes. Strain numbers are noted after the species names. Strains isolated in this study are presented in red and type strains are in bold.

FIGURE 6. Dothiorella albiziae on dead dry pod of Albizia lebbeck (holotype: MFLU 22-0093). a. Host. b, c. Conidiomata on dry pod surface. d. Vertical section through conidioma. e. Peridium of conidioma. f–i. Conidia attached to conidiogenous cells. j–m. Conidia. n, o. Colony on PDA (n upper, o lower). Scale bars: b = 2 mm, c = 500 μm, d = 100 μm, e–m = 10 μm.