College of Plant Protection, Biocontrol Engineering Laboratory of Crop Diseases and Pests of Gansu Province, Gansu Agricultural University, Lanzhou, 730070, China.
College of Plant Protection, Biocontrol Engineering Laboratory of Crop Diseases and Pests of Gansu Province, Gansu Agricultural University, Lanzhou, 730070, China.
Microb Pathog. 2022 Nov;172:105750. doi: 10.1016/j.micpath.2022.105750. Epub 2022 Sep 6.
Tussilago farfara is of vital medical value. A new leaf spot disease was observed on T. farfara leaves, in Dingxi, Gansu Province, China, in October 2019. In order to research the pathogen, the diseased samples were collected for isolation and identification. The isolate KD3 was verified by pathogenicity test, as the pathogen causing the T. farfara leaf spot disease. Its morphological characteristics were consistent with Alternaria alternata, the colony color gray-green with concentric rings, conidia fusiform and pear-shaped, brown, with 1-7 septa and 0-3 longitudinal septa, conidia size (19. 62-44.49) μm × (6.97-10.53) μm, beak length (1.35-10.03) μm × (1.01-3.63) μm, and the spore phenotype was a dwarf tree-like chain of short conidia. Multilocus sequences analysis manifested that the internal transcribed spacer (ITS), Alternaria major allergen (Alta1), and Calcium barine (CAL) sequences of strain KD3 were most closely to A. alternata (A23), with the homology of 99.47%, 99.56% and 98.28%, respectively. Based on morphological and molecular characteristics, strain KD3 was identified as A. alternata. OA was the optimal medium for its growth and PCA medium was the optimal for sporulation. This is the first report of A. alternata causing T. farfara leaf spots in China.
款冬是一种具有重要医疗价值的植物。2019 年 10 月，在中国甘肃定西观察到款冬叶片出现一种新的叶斑病。为了研究病原体，采集了患病样本进行分离和鉴定。通过致病性试验验证，分离株 KD3 是引起款冬叶斑病的病原菌。其形态特征与链格孢属（Alternaria alternata）一致，菌落颜色为灰绿色，有同心环，分生孢子为梭形和梨形，棕色，有 1-7 个隔膜和 0-3 个纵向隔膜，分生孢子大小为（19.62-44.49）μm×（6.97-10.53）μm，喙长（1.35-10.03）μm×（1.01-3.63）μm，孢子表型为短分生孢子的矮树状链式。多位点序列分析表明，菌株 KD3 的内部转录间隔区（ITS）、链格孢主要过敏原（Alta1）和钙调蛋白（CAL）序列与 A. alternata（A23）最为接近，同源性分别为 99.47%、99.56%和 98.28%。基于形态学和分子特征，菌株 KD3 被鉴定为 A. alternata。OA 是其生长的最佳培养基，PCA 培养基是其产孢的最佳培养基。这是在中国首次报道 A. alternata 引起款冬叶斑病。
