Diaporthe osmanthi H. Long, K.D. Hyde & Yong Wang bis

Long, Hui, Zhang, Qian, Hao, Yuan-Yuan, Shao, Xian-Qiang, Wei, Xiao-Xing, Hyde, Kevin D., Wang, Yong & Zhao, De-Gang, 2019, Diaporthe species in south-western China, MycoKeys 57, pp. 113-127 : 113

Diaporthe osmanthi H. Long, K.D. Hyde & Yong Wang bis sp. nov. Figure 4

Diagnosis.

Characterised by size of α-conidia and β-conidia.

Type.

China, Guangxi province, Nanning City, from leaves of Osmanthus fragrans , 20 September, 2016, Y. Wang, HGUP 9165, holotype, ex-type living culture GUCC 9165.

Description.

Colonies on PDA attaining 9 cm diam. after 10 days; coralloid with feathery branches at margin, adpressed, without aerial mycelium, with numerous irregularly zonated dark stromata, isabelline becoming lighter towards the margin; reverse similar to the surface with zonations more apparent. Conidiomata pycnidial and multilocular, scattered, abundant on PDA after 3 wks, globose, subglobose or irregular, up to 1-1.5 mm diam., ostiolate, necks absent or up to 1 mm. Conidiophores formed from the inner layer of the locular wall, reduced to conidiogenous cells or 1-septate, hyaline to pale yellowish-brown, cylindrical, 20.5-61 × 1-3 μm. Conidiogenous cells cylindrical to flexuous, tapered towards apex, hyaline, 10-15 × 1.5-3 μm. Alpha conidia abundant, fusiform, narrowed towards the apex and base, apparently biguttulate, hyaline, 5.5-8.5 × 2-3 μm. Beta conidia scarce to abundant, flexuous to J-shaped, hyaline, 20-31.5 × 1-2.5 μm. Perithecia not seen.

Habitat and distribution.

Isolated from leaves of Osmanthus fragrans in China.

Etymology.

Species epithet osmanthi , referring to the host, Osmanthus fragrans from which our strain was isolated.

Notes.

Diaporthe osmanthi (strain GUCC9165) formed an independent lineage, but was also related to D. arecae and D. hongkongensis ( Figure 1 ). The sequences of β -tubulin and tef 1 included about two-three differences between D. osmanthi (GUCC9165) and D. arecae (42) and D. hongkongensis (78) and thus they were different species according to the guidelines of Jeewon and Hyde (2016). Additionally, Diaporthe hongkongensis produced three types of conidia, but Diaporthe osmanthi did not produce γ-conidia. In addition, β-conidia of D. hongkongensis (18-22 μm) were shorter than those of Diaporthe osmanthi ( Gomes et al. 2013). According to original description Srivastava et al. (1962), D. arecae also produced two types of conidia. The α-conidia (7.2-9.6 × 2.4 μm) were longer than in Diaporthe osmanthi , but its β-conidia (14.4-24 × 1.2 μm) were shorter and their shape also had some differences.

Figures

Figure 1. Parsimonious tree obtained from a combined analyses of an ITS, β - tubulin, calmoudulin and tef 1 sequence dataset. MP, ML above 50 % and BPP values above 0.90 were placed close to topological nodes and separated by " / ". The bootstrap values below 50 % and BPP values below 0.90 were labelled with " - ". The tree is rooted with Valsa ambiens (CFCC 89894). The branch of our new Diaporthe species is in pink.

Figure 4. Diaporthe osmanthi (GUCC 9165). a-b upper (a) and lower (b) surface of colony on PDA c-d conidiomata e conidiophores, conidiogenous loci and conidia f α-conidia g two types of conidia h β-conidia. Scale bars: 10 µm (e, f, g, h).