Alternaria jingzhouensis S. L. L. Aung & J. X. Deng, 2024

Aung, Sein Lai Lai, Liu, Feng-Yin, Gou, Ya-Nan, Nwe, Zin Mar, Yu, Zhi-He & Deng, Jian-Xin, 2024, Morphological and phylogenetic analyses reveal two new Alternaria species (Pleosporales, Pleosporaceae) in Alternaria section from Cucurbitaceae plants in China, MycoKeys 107, pp. 125-139 : 125-139

Alternaria jingzhouensis S. L. L. Aung & J. X. Deng sp. nov.

Fig. 2

Type.

China, Hubei Province, Jingzhou city, Yangtze University (west campus) on infected leaves of Citrullus lanatus 2022, F. Y Liu, ( YZU - H- 2022030, holotype), ex-type culture YZU 221144.

Etymology.

Named after the collecting locality, Jingzhou (Hubei, China)

Description.

Colonies on PDA (7 d at 25 ° C) pale luteous to amber in the center, white at the edges, light to moderate rosy buff or pale saffron in reverse, cottony surface and 49–52 mm in diam., at 25 ° C for 7 days (Fig. 2 A, B ). On PCA (7 d at 22 ° C), conidiophores arising from substrate, simple, straight or flexuous, light to olivaceous buff, 41–99 (– 151) × 3.5–5 μm (x ̄ = 73 × 4.4 µm, n = 20), conidiogenous cells 5–11 × 3–6 µm (x ̄ = 8 × 4 µm, n = 20), mono- to polytretic, terminal, determinate, cylindrical, olivaceous buff, smooth, thin-walled, apically doliiform, with 1 conidiogenous locus cicatrized on conidial secession, sometimes swollen near conidiogenous loci; conidia 3–5 units per chain, arising from the apex or near the apex of the conidiophores or terminal hyphae, muriform, ellipsoidal, flask-shaped, rostrate, beaked, 28–51 × 11–21 μm (x ̄ = 38 × 16.4, n = 50), with 1–4 transverse septa with 0–2 branching (Fig. 2 C, E ); On V 8 A (7 d at 22 ° C), conidiophores 40–94 × 4–7 μm (x ̄ = 58 × 5, n = 20), simple, straight or flexuous, light to olivaceous buff; conidiogenous cells 5–13 × 3–6 µm (x ̄ = 8 × 4 µm, n = 20), mono- to polytretic, terminal, determinate, cylindrical, olivaceous buff, smooth, thin-walled, apically doliiform, with 1 conidiogenous locus, sometimes swollen near conidiogenous loci cicatrized on conidial secession; conidia 3–5 units per chain, arising from the apex or near the apex of the conidiophores or terminal hyphae, muriform, ellipsoidal, flask-shaped, rostrate, beaked, 22–51 × 3–16 μm (x ̄ = 33.9 × 13.2, n = 50), 1–6 transverse septa with 0–2 branching (Fig. 2 D, F ).

Additional isolate examined.

China, Hubei Province, Jingzhou city, Yangtze University (west campus) on infected leaves of Citrullus lanatus 2022, F. Y Liu, living culture YZU 221145.

Notes.

Phylogenetically, A. jingzhouensis sp. nov. is different from its sister species A. baoshanensis , A. koreana , A. momordicae sp. nov., A. orobanches and A. ovoidea based on sequences derived from seven genes (Fig. 1 ). After conducting a nucleotide pairwise comparison as recommended by Jeewon and Hyde (2016), the present species can be readily distinguished from the closet species A. koreana , A. momordicae sp. nov. and A. orobanches constructed on any of the ITS, GAPDH, TEF 1, RPB 2, Alt a 1, EndoPG, and OPA 10-2 genes, which has 1 bp difference in the ITS region, 1 bp in GAPDH, 1 bp in TEF 1, 7 pb in RPB 2, 9 bp in Alt a 1, 10 bp in EndoPG, and 4 bp in OPA 10-2 when compared with A. koreana , 1 bp in GAPDH, 4 bp in RPB 2, and 11 bp in OPA 10-2 when compared with A. momordicae sp. nov. and 49 bp differences in the ITS region when compared with sister species A. orobanches . Morphologically, the species is distinct from A. baoshanensis , A. koreana , and A. ovoidea as it produces conidia on a simple conidiogenous locus with occasionally longer beaks in a chain of 3–5 units, and from A. momordicae sp. nov. by having shorter beaks (Table 2 ).

Figures

Figure 1. Phylogenetic tree of the Alternaria species most related to the new taxa based on maximum likelihood analysis using the combined gene sequences of ITS, GAPDH, TEF 1, RPB 2, Alt a 1, EndoPG and OPA 10-2 which rooted with Alternaria alternantherae (CBS 124392) from sect. Alternantherae. The Bayesian posterior probabilities > 0.60 (PP) and bootstrap support values > 60 (BS) are given at the nodes (PP / BS). The novel species are highlighted in bold. Ex-type isolates are marked with a superscript T and Representative isolates are marked with a superscript R.

Figure 2. Alternaria jingzhouensis sp. nov. (ex-type YZU 221144) A, B seven-day-old culture on PDA C, D conidiophores and conidia on PCA and V 8 A, respectively E, F conidia on PCA and V 8 A, respectively. Scale bars: 25 μm (E, F); 50 μm (C, D).