Diaporthe smilacicola Y.Q. Zhu & Ning Jiang, 2023

Zhu, Ya-Quan, Ma, Chun-Yan, Xue, Han, Piao, Chun-Gen, Li, Yong & Jiang, Ning, 2023, Two new species of Diaporthe (Diaporthaceae, Diaporthales) in China, MycoKeys 95, pp. 209-228 : 209

Diaporthe smilacicola Y.Q. Zhu & Ning Jiang sp. nov.

Fig. 4

Etymology.

Named after the host genus, Smilax .

Description.

Leaf spots subcircular to irregular, pale brown to brown, with dark brown margin. Conidiomata pycnidial, scattered, subglobose to globose, black, erumpent, exuding faint yellow translucent conidial droplets from central ostioles, 150-350 μm diam. Conidiogenous cells 11-16.2 × 1.8-2.4 μm, hyaline, phialidic, cylindrical, terminal, slightly tapering towards the apex. Alpha conidia 5.7-9.7 × 2.0-3.5 μm (mean = 7.8 × 2.6 μm, n = 50), hyaline, aseptate, smooth, guttulate, ellipsoidal to oblong ellipsoidal, with both ends obtuse. Beta conidia and gamma conidia not observed. Sexual morph not observed.

Culture characters.

Colonies on PDA flat, with flocculent aerial mycelium and crenate edge, white to gray, reaching a 90 mm diameter after 14 days at 25 °C, forming black conidiomata with black conidial masses; on MEA flat, spreading, with flocculent aerial mycelium forming concentric rings, off-white to luteous, reaching a 90 mm diameter after 14 days at 25 °C; on SNA flat, spreading, with flocculent aerial mycelium forming concentric rings and entire edge, white, reaching a 90 mm diameter after 14 days at 25 °C.

Materials examined.

China, Hunan Province, Changsha City, Changsha County, Kaihui Town , on leaf spots of Smilax glabra , 2 November 2020, Ning Jiang (holotype CAF 800070; ex-holotype culture CFCC 54582) . Hunan Province, Shaoshan City , on leaf spots of Smilax glabra , 2 November 2020, Ning Jiang (cultures CFCC 58764 and CFCC 58765) .

Notes.

Three Diaporthe isolates representing D. smilacicola formed a well-supported clade (ML/BI = 100/1), and appear to be distinct from the other Diaporthe species phylogenetically (Fig. 2 ). Diaporthe eres (= D. mahothocarpi ), D. lithocarpi and D. smilacicola have been reported from the host S. glabra ( Gao et al. 2013; Chaisiri et al. 2021). Morphologically, these three species are similar in conidial shape and size. However, Diaporthe eres belongs to D. eres species complex, which is different from D. lithocarpi and D. smilacicola in D. arecae species complex. D. smilacicola is obviously different from D. lithocarpi based on sequence data (22/467 in ITS, 31/393 in cal, 52/317 in tef1, 19/420 in tub2) (Fig. 2 ).

Figures

Figure 2. Phylogram of Diaporthe arecae species complex resulting from a maximum likelihood analysis based on a combined matrix of ITS, cal, his 3, tef 1 and tub 2 loci. Numbers above the branches indicate ML bootstrap values (left, ML BS ≥ 50 %) and Bayesian posterior probabilities (right, BPP ≥ 0.9). Isolates from the present study are marked in bold blue.

Figure 4. Morphology of Diaporthe smilacicola A colonies on PDA, MEA and SNA at 25 ° C after 2 weeks B leaf spots on the host surface C conidiomata formed on the PDA D, E conidiogenous cells with attached alpha conidia F-G alpha conidia. Scale bars: 200 µm (C); 10 µm (D-G).