Diaporthe camelliae-sinensis 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 camelliae-sinensis S.T. Huang, J.W. Xia, X.G. Zhang & Z. Li sp. nov. Figure 2

Etymology.

Named after the host Camellia sinensis on which it was collected.

Diagnosis.

Diaporthe camelliae-sinensis can be distinguished from the closely related species D. macintoshii R.G. Shivas et al. and D. vangueriae Crous based on ITS, TUB and TEF loci. Diaporthe camelliae-sinensis differs from D. macintoshii in smaller α-conidia and from D. vangueriae in shorter β-conidia.

Type.

China, Yunnan Province: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, on infected leaves of Camellia sinensis . 19 April 2019, S.T. Huang, HSAUP194.92, holotype, ex-holotype living culture SAUCC194.92.

Description.

Asexual morph: Conidiomata pycnidial, multi-pycnidia grouped together, globose, black, erumpent, coated with white hyphae, thick-walled, exuding creamy to yellowish conidial droplets from central ostioles. Conidiophores hyaline, smooth, septate, branched, densely aggregated, cylindrical, straight to sinuous, swelling at the base, tapering towards the apex, 10-15 × 1.5-2 μm. Conidiogenous cells 8.5-12 × 2-2.8 μm, phialidic, cylindrical, terminal, slightly tapering towards the apex. Alpha conidia, hyaline, smooth, aseptate, ellipsoidal to fusoid, 2-4 guttulate, apex subobtuse, base subtruncate, 7.5-10 × 1.8-2.5 µm (mean = 8.5 × 2.2 μm, n = 20). Beta conidia hyaline, aseptate, filiform, sigmoid to lunate, mostly curved through 90-180°, tapering towards the apex, base truncate, 20-30 × 1.2-1.6 µm (mean = 25.6 × 1.3 μm, n = 20). Gamma conidia and sexual morph not observed.

Culture characteristics.

Pure culture was isolated by subbing hyphal tips growing from surface sterilized diseased material. Colonies on PDA cover the Petri dish diameter after incubation for 15 days in dark conditions at 25 °C, cottony and radially with abundant aerial mycelium, sparse in the margin. With a tanned concentric ring of dense hyphae, white on surface side, white to pale yellow on reverse side.

Additional specimens examined.

China, Yunnan Province: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, 19 April 2019, S.T. Huang. On infected leaves of Castanea mollissima , HSAUP194.103 and HSAUP194.104 paratype, living culture SAUCC194.103 and SAUCC194.104; on diseased leaves of Machilus pingii , HSAUP194.108 paratype, living culture SAUCC194.108.

Notes.

Four isolates are clustered in a clade distinct from its closest phylogenetic neighbor, D. macintoshii and D. vangueriae . Diaporthe camelliae-sinensis can be distinguished from D. macintoshii in ITS, TUB and TEF loci (23/558 in ITS, 2/463 in TUB and 20/328 in TEF); from D. vangueriae in ITS and TUB loci (23/558 in ITS and 1/423 in TUB). Morphologically, Diaporthe camelliae-sinensis differs from D. macintoshii in having guttulate alpha conidia and smaller alpha conidia (7.5-10 × 1.8-2.5 vs. 8.0-11.0 × 2.0-3.0 μm) ( Thompson et al. 2015). Furthermore, Diaporthe camelliae-sinensis differs from D. vangueriae in shorter beta conidia (20-30 × 1.2-1.6 vs. 28-35 × 1.5-2.0 μm) and D. camelliae-sinensis can produce alpha conidia, but D. vangueriae could not ( Crous et al. 2014).

Figures

Figure 2. Diaporthe camelliae-sinensis (SAUCC 194.92) a leaf of host plant b, c surface (b) and reverse (c) sides of colony after incubation for 15 days on PDA d conidiomata e-h conidiophores and conidiogenous cells i beta conidia j-l alpha conidia and beta conidia m alpha conidia. Scale bars: 10 μm (e-m).