Diaporthe pungensis S.T. Huang, J.W. Xia, X.G. Zhang, Z. Li, 2021

Sun, Wenxiu, Huang, Shengting, Xia, Jiwen, Zhang, Xiuguo & Li, Zhuang, 2021, Morphological and molecular identification of Diaporthe species in south-western China, with description of eight new species, MycoKeys 77, pp. 65-95 : 65

Diaporthe pungensis S.T. Huang, J.W. Xia, X.G. Zhang, Z. Li sp. nov. Figure 9

Etymology.

Named after the host Elaeagnus pungens on which it was collected.

Diagnosis.

Diaporthe pungensis differs from its closest phylogenetic species D. inconspicua R.R. Gomes et al. and D. poincianellae T.G.L. Oloveira et al. in ITS, TUB, TEF, CAL and HIS loci based on the alignments deposited in Tree-BASE.

Type.

China, Yunnan Province: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, on diseased leaves of Elaeagnus pungens . 19 April 2019, S.T. Huang, HSAUP194.112, holotype, ex-holotype living culture SAUCC194.112.

Description.

Asexual morph: Conidiomata pycnidial, 3-5 pycnidia grouped together, superficial to embedded on PDA, erumpent, thin-walled, dark brown to black, globose or subglobose, exuding white creamy conidial mass from the ostioles. Conidiophores hyaline, aseptate, cylindrical, smooth, straight to sinuous, unbranched, 11.0-14.5 × 1.5-2.3 µm. Conidiogenous cells phialidic, cylindrical, terminal, 8.0-9.5 × 1.0-2.5 µm. Alpha conidia, hyaline, smooth, aseptate, ellipsoidal to fusoid, 2-3 guttulate, apex subobtuse, base subtruncate, 6.0-8.5 × 2.0-3.3 µm (mean = 6.6 × 2.5 μm, n = 20). Beta conidia hyaline, aseptate, eguttulate, filiform, slightly curved, tapering towards the apex, base truncate, some conidia are in the immature stage swollen in the middle, 24.0-28.9 × 1.0-2.0 µm (mean = 26.9 × 1.4 μm, n = 20). Gamma conidia not observed, sexual morph not observed.

Culture characteristics.

Pure culture was isolated by subbing hyphal tips growing from surface sterilized plant material. Colonies on PDA cover the 3/4 of Petri dish diameter after incubation for 15 days in dark conditions at 25 °C, flat, cottony in the center with medium developed aerial mycelium, sparse in the outer region. With several concentric rings of dense and sparse hyphae, irregular margin, white on surface side, white to pale yellow and cinnamon speckle on reverse side.

Additional specimen examined.

China, Yunnan Province: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, on infected leaves of Camellia sinensis . 19 April 2019, S.T. Huang, HSAUP194.89 paratype, living culture SAUCC194.89.

Notes.

Diaporthe pungensis forms a distinct clade with high support (ML/BI = 100/1), and differed with the closely related species ( D. inconspicua and D. poincianellae ) on ITS, TUB, CAL and HIS loci (94% in ITS, 92% in TUB, 70% in TEF, 92% in CAL and 92% in HIS; and 95% in ITS, 94% in TUB, 80% in TEF, 94% in CAL and 89% in HIS, respectively). Moreover, Diaporthe pungensis differs from D. inconspicua , in having guttulate of alpha conidia, and having larger alpha conidia (6.0-8.5 × 2.0-3.3 vs. 5.5-6.5 × 1.5-2 μm) ( Bezerra et al. 2018). Furthermore, Diaporthe pungensis can produce two types of conidia (α-conidia and β-conidia), but D. poincianellae only produce a α-conidia ( Crous et al. 2018b).

Figures

Figure 9. Diaporthe pungensis (SAUCC 194.112) a leaf of host plant b, c surface (b) and reverse (c) sides of colony after incubation for 15 days on PDA d conidiomata on PDA e-h conidiophores and conidiogenous cells i, l beta conidia j, k alpha conidia and beta conidia. Scale bars: 10 μm (e-l).