Alternaria oryzicola H. F. Liu & J. X. Deng sp. nov.

Fig. 2

Etymology.

Name refers to its host Oryza sativa.

Type.

China • Hainan Province, Lingshui County, diseased leaves of Oryza sativa, July 2023, J. L. Yin, holotype YZU-H-2023056 A (permanently preserved in a metabolically inactive state), ex-type culture YZU 231199.

Description.

Colonies on PDA sub-circular, velvety to fluffy, white to greyish-green, darker at the center, reverse side pale yellow to light brown, 61–63 mm in diameter (Fig. 2 a). On PCA, conidiophores, erect or curved, unbranched, sometimes slightly expanded at the apex, 32–105 × 3–4 μm in size, with 1–6 septa (Fig. 2 f). Conidiogenous cells integrated, terminal, smooth, cylindrical, apically doliiform, 5–14 × 3–4 μm, with 1 conidiogenous locus. Conidia borne in chain, 1–3 units per chain, unbranched, mostly narrow-obclavate, obclavate, or long ellipsoid, 20–48 × 9–16 μm in dimension, 1–4 transverse septa, apical beak 4–39 × 2.5–4 μm (Fig. 2 b, c, g). On V 8 A, conidiophores unbranched, 20–67 × 3–4 μm, with 1–5 septa. Conidia solitary or in chain with 2–3 units per chain, narrow-obclavate, obclavate, or long ellipsoid, 18–56 × 9–16 μm in size, with 2–6 transverse septa, apical beak 4–39 μm in length, 3–4 μm in width (Fig. 2 d, e, h).

Notes.

Based on phylogenetic analysis using combined dataset of multiple regions, strain YZU 231199 was relatively close to strains of Alternaria tomato (CBS 103.30 and CBS 114.35). Comparative analysis of nucleotide sequences revealed that strain YZU 231199 differed from representative strain of A. tomato (CBS 103.30) at four regions: 3 bp differences in GAPDH with 1 gap; 4 bp differences in RPB 2, 1 bp difference in TEF 1, and 1 bp difference in OPA 10-2. Morphologically, the present fungus (YZU 231199) was also different with A. tomato in having smaller body size, less septa, and shorter beak (Table 2). Therefore, strain YZU 231199 was introduced as a novel species A. oryzicola sp. nov. in this study.