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

Fig. 3

Type.

China, Sichuan Province, Deyang city infected leaves of Momordica charantia . 2016, J. X Deng, ( YZU - H- 2016001, holotype), ex-type culture YZU 161378.

Etymology.

Refers to the host genus, Momordica .

Description.

Colonies on PDA (7 d at 25 ° C) greyish yellow-green, light white at the edge, buff to salmon in reverse, surface compact, 50–55 mm in diam. (Fig. 3 A, B ). On PCA (7 d at 22 ° C), conidiophores arising from substrate, simple, straight or flexuous, septate, olivaceous buff to olivaceous, 26.5–93 × 3–4 μm (x ̄ = 59.5 × 3.8 μm, n = 20); conidiogenous cells 5–10 × 3–5 µm (x ̄ = 7 × 4 µm, n = 20), mono- to polytretic, terminal, determinate, cylindrical, olivaceous buff to olivaceous, smooth, thin-walled, apically doliiform, with 1 conidiogenous locus cicatrized on conidial secession, sometimes swollen near conidiogenous loci; conidia 3–4 units per chain, arising from the apex or near the apex of the conidiophores or terminal hyphae, muriform, long ellipsoid or ovoid to obclavate, sometime inverted club-shaped, 6–42 × 4–34 μm (x ̄ = 32.8 × 13.5 μm, n = 50), 1–5 transverse septa, apical beak 2–19.5 μm long and 1–2 septa (Fig. 3 C, E ); On V 8 A (7 d at 22 ° C), conidiophores straight or curved, smooth-walled, olivaceous buff 23–63 (– 208) × 3–5 μm (x ̄ = 64.9 × 4.2 μm, n = 20); conidiogenous cells 5–13 × 3–4 µm (x ̄ = 7 × 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 3–4 units per chain, muriform, long ellipsoid or ovoid to obclavate, inverted club-shaped, 24–61 × 10 – 17 μm (x ̄ = 39 × 14.3 μm, n = 50), 1–5 transverse septa with apical beak 3–25.5 μm long and 1–2 septa (Fig. 3 D, F ).

Additional isolate examined.

China, Sichuan Province, Deyang city infected leaves of Momordica charantia . 2016, J. X Deng, living culture YZU 161379.

Notes.

After the combined dataset of ITS, GAPDH, TEF 1, RPB 2, Alt a 1, EndoPG and OPA 10-2 gene fragments, A. momordicae sp. nov. is readily distinguished from its sister species A. baoshanensis , A. jingzhouensis sp. nov., A. koreana , and A. ovoidea , (Fig. 1 ). After a nucleotide pairwise comparison as suggested by Jeewon and Hyde (2016), the present species can be readily distinguished from the closet species A. koreana and others related a novel species based 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, 4 bp in RPB 2, 8 bp in Alt a 1 and 10 bp in EndoPG when compared with A. koreana and 1 bp in GAPDH, 4 bp in RPB 2, and 11 bp in OPA 10-2 when compared with A. jingzhouensis sp. nov.. Morphologically, A. momordicae sp. nov. produces conidia on PCA that are significantly shorter than those on V 8 A. It can be distinguished from A. baoshanensis , A. koreana , and A. ovoidea by producing conidia on a single conidiogenous locus with a wider body and longer beak in a chain of 3–4 units. Additionally, it differs from A. jingzhouensis sp. nov. by having a longer beak (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 3. Alternaria momordicae sp. nov. (ex-type YZU 161378) 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).