Diaporthe middletonii R.G. Shivas, L. Morin, S.M. Thomps. & Y.P. Tan, Persoonia 35: 45. (2015)

Huang, Shengting, Xia, Jiwen, Zhang, Xiuguo & Sun, Wenxiu, 2021, Morphological and phylogenetic analyses reveal three new species of Diaporthe from Yunnan, China, MycoKeys 78, pp. 49-77 : 49

Diaporthe middletonii R.G. Shivas, L. Morin, S.M. Thomps. & Y.P. Tan, Persoonia 35: 45. (2015) Figure 6

Description.

Asexual morph: Leaf spots discoid to irregular. Conidiomata pycnidial, scattered or aggregated in groups of 3-5 pycnidia, globose, black, erumpent, coated with white to greyish hyphae, thick-walled, exuding creamy translucent conidial droplets from central ostioles. Conidiophores hyaline, smooth, septate, unbranched, densely aggregated, cylindrical, straight to sinuous, tapering towards apex, 10.0-14.0 × 1.3-2.3 μm. Conidiogenous cells 5.0-9.5 × 1.3-1.7 μm, phialidic, cylindrical, terminal, slightly tapering towards apex. Alpha conidia hyaline, smooth, aseptate, biguttulate, ellipsoidal, oval, apex subobtuse, base subtruncate, 5.5-7.0 × 2.5-3.2 µm (mean = 6.3 × 2.8 μm, n = 20). Beta conidia hyaline, aseptate, filiform, mostly curved by 90-180°, tapering towards both ends, 26.0-36.5 × 1.0-1.6 µm (mean = 21.5 × 1.2 μm, n = 20). Gamma conidia not observed. Sexual morph not observed.

Culture characteristics.

Cultures incubated on PDA at 25 °C in darkness, growth rate 22.5-24.0 mm diam/day, fluffy with abundant aerial mycelium, margin fimbriate, white on surface, white to pale yellow on reverse.

Specimens examined.

China, Yunnan Province: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, 19 April 2019, S.T. Huang. On diseased leaves of Litchi chinensis ( Sapindaceae ), HSAUP194.27, living culture SAUCC194.27; on diseased leaves of Lithocarpus glaber ( Fagaceae ), HSAUP194.45, living culture SAUCC194.45; on diseased leaves of Lithocarpus glaber ( Fagaceae ), 19 April 2019, S.T. Huang, HSAUP194.46, living culture SAUCC194.46; on diseased leaves of Lithocarpus craibianus ( Fagaceae ), HSAUP194.48, living culture SAUCC194.48.

Notes.

Diaporthe middletonii was originally described from the stem of Rapistrum rugosum (BRIP 54884e) ( Brassicaceae ) and Chrysanthemoides monilifera subsp. rotundata (BRIP 57329) ( Asteraceae ) in Australia ( Thompson et al. 2015). In the present study, four strains (SAUCC194.27, SAUCC194.45, SAUCC194.46 and SAUCC194.48) are closely related to D. middletonii in the combined phylogenetic tree (Fig. 1 ). The differences between nucleotides in the concatenated alignment (17/565 in ITS, 9/494 in TUB and 10/340 in TEF) were minor. Morphologically, our strains were similar to D. middletonii by slightly shorter and wider alpha conidia (5.0-7.0 × 2.5-3.2 vs. 6.0-7.5 × 2.0-2.5 μm), and longer beta conidia (26.0-36.5 × 1.0-1.6 vs. 20.0-35.0 × 1.0-1.5 μm) ( Thompson et al. 2015). We therefore identify our strains as Diaporthe middletonii .

Figures

Figure 1. Phylogram of Diaporthe spp. based on combined sequence data of ITS, TUB, TEF, CAL and HIS genes. The ML and BI bootstrap support values above 50 % and 0.90 BYPP are shown at the first and second position, respectively. Strains marked with " * " are ex-type or ex-epitype. Codes referring to strains from the current study are written in red. Some branches were shortened to fit them to the page as indicated by two diagonal lines with the number of times a branch was shortened indicated.

Figure 6. Diaporthe middletonii (SAUCC 194.46) a infected leaf of Lithocarpus glaber b, c surface and reverse of colony after 15 days on PDA d, e conidiomata f-i conidiophores and conidiogenous cells j beta conidia k, l alpha conidia and beta conidia. Scale bars: 10 μm (f-l).