First Report of Taraxacum kok-saghyz Rodin Root Rot Caused by Alternaria tenuissima in Heilongjiang Province, China.

作者：Guoen Ao, Qinqin Nie, Xiaoyu Chen, Juanying Wang, Xuchu Wang · 发表于：Plant Disease · 年份：2025 · DOI：10.1094/pdis-12-24-2759-pdn · 被引用次数：2 · 研究领域：Medicine

Taraxacum kok-saghyz Rodin (TKS) is a perennial herb of the Asteraceae family, which is an important natural rubber supplement crop (Yang et al., 2023). In May 2023, a severe root rot disease was observed in TKS during cultivation in Harbin (45°75'N, 126°66'E), Heilongjiang Province, China. Field surveys indicated a disease incidence of approximately 10% within the 450 m2 cultivation area (500 TKS seedlings), with symptoms including leaf wilting, stunted growth, root necrosis, and plant mortality. To isolate its pathogen, nine symptomatic root segments (about 1 cm) were randomly sampled from three diseased plants and surface sterilized in 2% NaClO for 30 s, rinsed three times with sterile distilled water, and then incubated on potato dextrose agar (PDA) supplemented with 30 mg/L streptomycin at 28 °C in darkness for 3 days. Nine isolates with similar colony morphology were obtained from nine diseased root segments by mycelial tip separation. All isolates exhibited cottony colonies on the PDA medium, initially gray-white and then turned into dark gray, with the reverse side becoming black. On potato carrot agar medium, the conidia of these isolates are oval, brown in color, simple or form unbranched chains, and have 1-4 transverse septa and 0-2 longitudinal septa; they measured 10.23 to 30.57 μm in length and 5.48 to 9.96 μm in width (n = 50), exhibiting morphological characteristics consistent with members of the genus Alternaria (Simmons et al., 2007). Three isolates (GURF-0...