Alternaria guizhouensis W. Zhao, Q. Ning, & J.Y. Yan, sp. nov

MycoBank number: MB 558426; Index Fungorum number: IF 558426; Facesoffungi number: FoF 10796;

Description

Asexual morph: Hyphae subhyaline to pale olivaceous, branched, smooth, septate. Conidiophores 18—116×4—6 μm(x̅ =40.1×4.7 μm,n = 20), solitary, simple, straight, or flexuous, dark brown, multi-septate, with a single or two terminal conidiogenous loci. Conidia 15—38× 8—13 μm(x̅ =27.7×10.6 μm,n = 50), solitary or in branched chains of 4 or more, straight, clavate to elongated clavate, olivaceous to light brown, with a smooth outer wall, some muriform, usually with 4–6 transverse septa and 0–1 longitudinal septum, rounded apex, stalked or stalkless. Sexual morph: not observed.

Culture characteristics – Colonies on PCA attaining 80 mm diam. after 8-9 days at 25 °C in 12h light and 12h dark, circular, entire-edged, effuse, floccose to woolly, surface pale olivaceous grey- white near the margin changing to dull green in the centre and reverse olivaceous black in the centre and pale olivaceous grey near the margin.

Material examined: China, Guizhou Province, from Astragalus sinicus flower, May 2018, Zhao Wensheng, and Zhang Guozhen (JZBH 3180067 holotype) living culture = JZB 3180067.

Additional material examined – China, Henan Province, Shihe District, from Astragalus sinicus stem, May 2018, Zhao Wensheng and Zhang Guozhen, living culture = JZB 3180068, Guangxi Province, Guilin City, from Astragalus sinicus leaf, May 2018, Zhao Wensheng and Zhang Guozhen, living culture = JZB 3180069.

Distribution: China

Notes: We have recovered three isolates from Astragalus sinicus flowers, leaves, and stems that fit well with the species concept of Alternaria. Multi-marker analysis revealed that Alternaria guizhouensis isolates form a sister clade to A. henanensis; another novel species recovered in this study (Fig. 11) with 64% ML support. Morphological comparison between the ex-type strain of Alternaria guizhouensis and A. henanensis revealed different conidial characters. Compared to Alternaria guizhouensis, A. henanensis has small conidiophores (24.9– 118.8×2.5– 4.5 μm vs 18– 48.5 × 2.5–6 μm), larger conidia (10.5–29.7×6.7–12.1 μm vs 16– 30.2 × 5– 13 μm), also A. guizhouensis produced conidia in branched chains of 4 or more, while A. henanensis produced conidia in branched chains of three. Further these two species also can distinguish by the septa in conidia; A. guizhouensis have 4–6 transverse septa and 0–1 longitudinal septum while, A. henanensis produce conidia with 3–7 transverse septa and 0–1 longitudinal septum.

Fig. x. Alternaria guizhouensis (JZBH 3180067 holotype) a. Upper view of the colony on PCA, b. Back view of the colony on PCA, c. Conidiophore, d-f. Conidia, g. Conidial arrangement. Scale bars: c = 20 µm, d-f= 10 µm, g= 20 µm.