Botryosphaeria osmanthuse J. E. Sun, C. R. Meng & Yong Wang bis, 2022

Sun, Jing-E, Meng, Chao-Rong, Phillips, Alan J. L. & Wang, Yong, 2022, Two new Botryosphaeria (Botryosphaeriales, Botryosphaeriaceae) species in China, MycoKeys 94, pp. 1-16 : 1

Botryosphaeria osmanthuse J. E. Sun, C. R. Meng & Yong Wang bis sp. nov.

Figs 3a-i

Etymology.

In reference to the host from which the fungus was first isolated.

Diagnosis.

Botryosphaeria osmanthuse is characterised by aseptate narrowly fusiform conidia (16.0-20.5 × 5.0-6.0 µm (average = 17.0 × 5.3 µm, n = 45, L/W = 3.2) and short-length conidiogenous cells (8.5-10.5 × 2.3-2.8 µm), with moderate growth rate.

Type.

China, Guangxi Province, Nanning City , 22°51'N, 108°19'E, from leaves of Osmanthus fragrans , 20 October 2017, C.R. Meng, HGUP 21433 (holotype), ex-type living culture GUCC 21433 .

Description.

Saprobic on living leaves of Osmanthus fragrans . Teleomorph: Not observed. Anamorph: Conidiomata up to 200 µm diam., covered with hyphae, black, globose, ostiolate, solitary, separate, uniloculate, immersed to semi-immersed. Conidiomatal wall composed of thick-walled, dark brown cells of textura angularis, becoming thin-walled and hyaline towards the inner region. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 8.5-10.5 × 2.3-2.8 µm (average = 10 × 2.5 µm, n = 20), holoblastic, discrete, hyaline, cylindrical to lageniform, phialidic with periclinal thickening. Paraphyses not were seen. Conidia 16.0-20.5 × 5.0-6.0 µm (average = 17.0 × 5.3 µm, n = 45, L/W = 3.2), hyaline, thin-walled, smooth with granular contents, unicellular, aseptate narrowly fusiform, base subtruncate to bluntly rounded.

Culture characteristics.

Conidia germinate on PDA within 24 hours at room temperature (25 °C) with germ tubes produced from both ends of the conidia. Colonies with white fluffy mycelium on PDA (90 mm), after 7 days becomes raised, fluffy, white mycelium, dense filamentous.

Distribution.

China, Guangxi Province, Nanning City.

Other material examined.

China, Guangxi Province, Nanning City , 22°51'N, 108°19'E, from living leaves of Osmanthus fragrans , 20 October 2017, C.R. Meng, HGUP 21433, living culture GUCC 21433.1 and GUCC 21433.2 .

Notes.

NCBI BLAST searches of ITS sequences from our strains suggest a high degree of similarity (99-100%) to Botryosphaeria dothidea . However, DNA bases in the two loci (tef1 and tub2) showed a high amount of difference between B. osmanthuse and B. dothidea . Botryosphaeria osmanthuse shows close phylogenetic affinity to B. puerensis (Fig. 1 ). Comparing the morphological characteristics, conidia of B. osmanthuse (av. 17.0 × 5.3; L/W = 3.2) are narrower and shorter than B. puerensis (av. 26.8 × 6.4; L/W = 4.2) ( Li et al. 2020). Botryosphaeria osmanthuse was first isolated from Osmanthus fragrans ( Oleaceae ), while B. puerensis has been reported from Eucalyptus urophylla ( Myrtaceae ).

Figures

Figure 1. Trees resulting from MP analysis of the combined ITS, rpb 2, tef 1 and tub 2 sequence alignment for forty-three isolates in Botryosphaeria. RAxML and MP bootstrap support values (ML, MP ≥ 70 %) and Bayesian posterior probability (PP ≥ 0.90) are denoted on the nodes (ML / MP / PP). The tree was rooted to Neoscytalidium dimidiatum (CBS 145.78 and CBS 251.49) and Cophinforma atrovirens (MFLUCC 11 - 0425 and MFLUCC 11 - 0655). The new species are highlighted in pale red. The scale bar indicates 8.0 expected changes per site.

Figure 3. Botryosphaeria osmanthuse (GUCC 21433, holotype) a-c colonies on natural substrate d section through conidiomata e-g conidiophores and conidia h conidia i colony on PDA (left: above, right: reverse). Scale bars: 300 µm (b); 140 µm (c); 50 µm (d); 20 µm (e); 10 µm (f-h); 15 mm (i).