Alternaria oryzicola H. F. Liu & J. X. Deng, 2025

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

Fig. 2 View Figure 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 About YZU .

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 View Figure 2 ). 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 View Figure 2 ). 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 View Figure 2 ). 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 View Figure 2 ).

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 View Table 2 ). Therefore, strain YZU 231199 was introduced as a novel species A. oryzicola sp. nov. in this study.