Alternaria divaricatae L. He & J.X. Deng, 2021

He, Lin, Cheng, Hong, Zhao, Lin, Htun, Aye Aye, Yu, Zhi He, Deng, Jian Xin & Li, Qi Li, 2021, Morphological and molecular identification of two new Alternaria species (Ascomycota, Pleosporaceae) in section Radicina from China, MycoKeys 78, pp. 187-198 : 187

Alternaria divaricatae L. He & J.X. Deng sp. nov. Figure 2

Type.

China, Sichuan Province, Chengdu City, Wenjiang District, Herb Garden of Chengdu University of Traditional Chinese Medicine , from leaf spot of Saposhnikovia divaricata . 17 June, 2015, J.X Deng, (YZU-H-0029, holotype), ex-type culture YZU 151055 .

Etymology.

In reference to the host species name, Saposhnikovia divaricata .

Description.

Colonies on PDA (Fig. 2A ) vinaceous buff, hazel in the center, velvety, cottony, dark mouse grey to pale mouse grey in reverse, 56-64 mm in diam.; On PCA, conidiophores arising directly from lateral or apical of aerial hyphae or medium, lightly flexuous, sometimes geniculate at apex, smooth-walled, 9-36 × 3.5-6 μm, 1-3 transverse septa, the aerial hyphae sometimes up to 82-400 × 4-6 μm; conidia solitary from apex or geniculate loci, short-ovoid, subglobose, ellipsoid, 21-38 × 12-26 μm, with 1-4 transverse septa and 1-4 longitudinal septa (Fig. 2B, D, E ); On V8A, conidiophores 10-26 (-53) × 3-4 μm, 1-7 transverse septa, conidia 22-39 × 13-24 μm, 1-4 transverse septa, 1-3 longitudinal or oblique between septa (Fig. 2C, F, G ). There was no secondary conidium production observed on PCA and V8A medium.

Additional isolate examined.

China, Sichuan Province, Chengdu City, Wenjiang District, Herb Garden of Chengdu University of Traditional Chinese Medicine, from leaf spot of Saposhnikovia divaricata . 17 June, 2015, L He, living culture YZU 151059.

Notes.

Phylogenetically, Alternaria divaricatae forms a distinct clade in section Radicina , which appears to be sister to a clade including A. petroselini , A. selini and A. vulgarae (Fig. 1 ). Morphologically, A. divaricatae was different from A. petroselini , A. selini and A. vulgarae by producing smaller conidia (Table 2 ) and special sporulation from apex or geniculate loci of lateral or apical of aerial hyphae. Moreover, A. chlamydosporifera , A. glehniae and A. smyrnii grouped together and clustered as a sister clade with A. divaricatae , A. petroselini , A. selini and A. vulgarae (Fig. 1 ). Obviously, the conidia of A. divaricatae was smaller than A. smyrnii (Table 2 ) and A. divaricatae could be also easily differentiated from A. chlamydosporifera by the lack of chlamydospores in culture ( Marin-Felix et al. 2019). Meanwhile, A. glehniae was distinguished from A. divaricatae by its single conidium on apex of conidiophore (there was no geniculate sporulation loci) and production of secondary conidium ( Tao et al. 2019). In addition, A. radicina and A. carotiincultae were distinguished from present species by distant phylogenetic relationship in section Radicina .

Figures

Figure 1. Phylogenetic tree based on the combined gene sequences of ITS, TEF 1, GAPDH, and RPB 2. The Bayesian posterior probabilities> 0.70 (PP), maximum likelihood and maximum parsimony bootstrap support values> 70 (BS) are given at the nodes (PP / BS). Examined strains are in bold.

Figure 2. Morphological characteristics of Alternaria divaricatae (strain: YZU 151055). Colony on PDA for 7 days at 25 ° C (A); Conidia on PCA and V 8 A (B, C); Sporulation patterns from PCA and V 8 A (D-G: D, E from PCA F, G from V 8 A); Scale bars: 25 µm (B, C); 2 µm (D, F); 50 µm (E); 100 µm (G).