Diaporthe millettiae 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 millettiae H. Long, K.D. Hyde & Yong Wang bis sp. nov. Figure 3

Diagnosis.

Characterised by larger J-shaped β-conidia.

Type.

China, Guangxi Province, Nanning City, from leaves of Millettia reticulata , 20 September 2016, Y. Wang, HGUP 9167, holotype, ex-type living culture GUCC 9167.

Description.

Colonies on PDA attaining 9 cm diam. after 10 days; coralloid with feathery branches at margin, adpressed, with apparent aerial mycelium, with numerous irregularly zonate dark stromata, isabelline becoming lighter towards the margin; reverse similar to surface, with zonations. Conidiomata pycnidial, multilocular, scattered, abundant on PDA after 3 wks, subglobose to irregular, 1.5-1.8 mm diam., ostiolate, with up to 1 mm necks when present. Conidiophores formed from the inner layer of the locular wall, sometimes reduced to conidiogenous cells, when present 1-septate, hyaline to pale yellowish-brown, cylindrical, 10-23 × 1-2.5 μm. Conidiogenous cells cylindrical to flexuous, tapered towards apex, hyaline, 8-18 × 1.5-3 μm. Alpha conidia abundant, fusiform, narrowed towards apex and base, mostly biguttulate, hyaline, 4.5-9 × 2-3.5 μm. Beta conidia scarce to abundant, flexuous to J-shaped, hyaline, 17.5-32 × 1-2 μm. Perithecia not seen.

Habitat and distribution.

Isolated from leaves of Millettia reticulata in China

Etymology.

Species epithet millettiae , referring to the host, Millettia reticulata from which the strain was isolated.

Notes.

Phylogenetic analysis combining four gene loci showed that Diaporthe millettiae (strain GUCC 9167) displayed a close relationship with D. arengae , D. pseudomangiferae and D. perseae with high bootstrap values ( Figure 1 ). We compared the DNA base pair differences of the four gene regions, the main differences being in the β -tubulin and tef 1 genes, especially tef 1. Diaporthe millettiae produced two types of conidia (α, β), whereas D. pseudomangiferae only produced alpha conidia and D. perseae produced three types of conidia (α, β, γ). The β-conidia of D. arengae were smaller (20-25 × 1.5 μm) than those of Diaporthe millettiae (17.5-32 × 1-2 μm). The shape of β-conidia was also different. Conidiophores of D. arengae (10-60 μm) with more septa (0-6), were longer than those of D. millettiae (10-23 × 1-2.5 μm; 0-1-septate) ( Gomes et al. 2013).

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 3. Diaporthe millettiae (GUCC 9167). a-b upper (a) and lower (b) surface of colony on PDA c-d conidiomata e-f conidiophores, conidiogenous loci and conidia g β-conidia h α-conidia. Scale bars: 20 µm (e, f), 10 µm (g, h).