箭筈豌豆炭疽病病原菌分离鉴定

箭筈豌豆炭疽病是一类重要的真菌性病害。采用形态学特征观察结合基于内转录间隔区(ITS)、肌动蛋白(ACT)、几丁质酶(CHS1)和3-磷酸甘油醛脱氢酶(GADPH) 4个基因序列的多基因系统发育分析方法来鉴定甘肃夏河箭筈豌豆炭疽病的病原菌。结果表明,菌株WQ在马铃薯葡萄糖琼脂(PDA)培养基上的菌落平坦,正面为深灰色-橄榄色至橄榄色-黑色,边缘菌丝白色,背面灰色-橄榄色至铁灰色。分生孢子单胞透明,大小为(17.5~25.0) μm×(3.75~5.00) μm,略呈镰刀形。菌株WQ与编号为CBS 128.57的菌株同源性最高,在70%水平上聚为一支。病原菌可以通过伤口侵染箭筈豌豆叶片。确定箭筈豌豆炭疽病病原菌为菠菜炭疽菌,这是箭筈豌豆菠菜炭疽菌在中国的首次报道。寄主范围测定结果表明,病原菌对红豆草和燕麦均具有强致病性,对4个品种的箭筈豌豆具有中等致病性,对苜蓿和三叶草的致病性最低,而对黑麦草无致病性。

Isolation and identification of an anthracnose pathogen on Vicia sativa

Anthracnose in Vicia sativa is an important fungal disease affecting leaves and stems. This research combined morphological and multiple gene phylogenetic analyses, using gene sequences of an internal transcribed spacer region, actin, chitin synthase 1 and glyceraldehyde-3-phosphate dehydrogenase to identify an anthracnose pathogen (WQ) isolated from leaves and stems of vetch plants (cv. Lanjian No.2) in Xiahe County, Gansu Province. Koch’s postulates were applied to identify pathogenicity of the strains. It was found that colonies of the fungus on potato dextrose agar (PDA) were flat, with surface dark gray-olivaceous to olivaceous-black, white margin, covered by short floccose whitish aerial mycelium, reverse gray-olivaceous to iron-gray. Conidia were hyaline, unicellular, (17.5-25.0) μm×(3.75-5.00) μm, and slightly falcate. Multiple-gene phylogenetic analysis indicated that the isolate WQ and a strain of CBS 128.57 were clustered into one clade, with a confidence level of 70%. The strains (WQ) could infect V. sativa leaves through wounds. It was confirmed that the pathogen was Colletotrichum spinaciae. This is the first report of C. spinaciae on V. sativa in China. A host range test showed that C. spinaciae exhibited high pathogenicity to Onobrychis viciifolia and Avena sativa, and moderate pathogenicity to four V. sativa cultivars, and low pathogenicity to Medicago sativa and Trifolium repens. However, Colletotrichum spinaciae had no pathogenicity to Lolium multiflorum.