Diaporthe pometiae S.T. Huang, J.W. Xia, W.X. Sun, & X.G. Zhang, 2021

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 pometiae S.T. Huang, J.W. Xia, W.X. Sun, & X.G. Zhang sp. nov. Figure 9

Etymology.

Named after the host genus on which it was collected, Pometia pinnata .

Diagnosis.

Diaporthe pometiae is similar to D. biconispora but differs in having smaller alpha conidia (5.7-8.3 × 2.2-3.0 vs. 6.0-10.5 × 2-3.5 μm) and types of conidia ( D. pometiae produces beta conidia unlike D. biconispora ).

Type.

China, Yunnan Province: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, on diseased leaves of Pometia pinnata ( Sapindaceae ). 19 April 2019, S.T. Huang, HSAUP194.72 holotype, ex-type living culture SAUCC194.72.

Description.

Asexual morph: Leaf spots subcircular, fawn to dark brown. Conidiomata pycnidial, subglobose to globose, aggregated in groups, black, coated with white hyphae, thick-walled, exuding creamy droplets from ostioles. Conidiophores hyaline, smooth, slightly septate, branched, densely aggregated, cylindric-clavate, straight to slightly sinuous, 22.5-32.5 × 1.0-2.0 μm. Conidiogenous cells 15.0-22.5 × 1.0-1.5 μm, phialidic, cylindrical, multi-guttulate, terminal, tapering towards apex. Alpha conidia abundant in culture, 2-4 guttulate, hyaline, smooth, aseptate, ellipsoidal to oblong ellipsoidal, with both ends obtuse, 5.7-8.3 × 2.2-3.0 µm (mean = 6.7 × 3.1 μm, n = 20). Beta conidia, hyaline, aseptate, filiform, multi-guttulate, slightly curved, tapering towards to apex, 27.8-34.5 × 1.0-1.7 µm (mean = 21.7 × 1.4 μm, n = 20). Gamma conidia not observed. Sexual morph not observed.

Culture characteristics.

Cultures incubated on PDA at 25 °C in darkness, growth rate 11.5-13.0 mm diam/day, cottony with abundant aerial mycelium, with a concentric zonation, white on surface, white to grayish on reverse.

Additional specimens examined.

China, Yunnan Province: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, 19 April 2019, S.T. Huang. On diseased leaves of Persea americana ( Lauraceae ), HSAUP194.19 paratype, ex-paratype culture SAUCC194.19; on diseased leaves of Heliconia metallica ( Musaceae ), HSAUP194.73 paratype, ex-paratype culture SAUCC194.73.

Notes.

Diaporthe pometiae is introduced based on the multi-locus phylogenetic analysis, with three isolates clustering separately in a well-supported clade (ML/BI = 100/1). Diaporthe pometiae is most closely related to D. biconispora , but distinguished based on ITS, TUB, TEF and HIS loci by 74 nucleotide differences in the concatenated alignment, in which 2/492 are distinct in the ITS region, 8/353 in the TUB region, 49/370 in the TEF region and 15/471 in the HIS region. Morphologically, Diaporthe pometiae differs from D. biconispora in its smaller alpha conidia (5.7-8.3 × 2.2-3.0 vs. 6.0-10.5 × 2-3.5 μm). Furthermore, Diaporthe pometiae produces beta conidia unlike D. biconispora ( Huang et al. 2015).

Figures

Figure 9. Diaporthe pometiae (SAUCC 194.72) a infected leaf of Pometia pinnata b, c surface and reverse of colony after 15 days on PDA d conidiomata e, f conidiophores and conidiogenous cells g beta conidia h alpha conidia and beta conidia. Scale bars: 10 μm (e-h).