一株西藏白菜型黄籽油菜黑斑病菌的鉴定及生物学特性

摘要

To clarify the causal agent of rape black spot disease in Linzhi area,rape plant with black spot symptom was collected in field. An Alternaria isolate(XZ - S1)was obtained,and its pathogenicity on leaf was in-vestigated by Koch's postulates. Strain XZ - S1 was identified using rDNA - ITS(ribosomal DNA internal tran-scribed spacer)sequences. Result showed that XZ - S1 clustered with Alternaria brassicae at 98% bootstrap levels in phylogenetic tree. The optimum growth condition for the pathogen was PSA(potato sugar agar medium)with starch(carbon source),peptone(nitrogen source),at 25℃ under pH6. 5 - 7. 5. The highest spore yield was ob-tained on PCA(potato carrot agar)medium.%为明确西藏林芝地区油菜黑斑病的病原物，从发病田采集病株，采用组织分离法得到一株链格孢菌 XZ- S1，用柯赫氏法则对该菌进行致病性测定，结合形态学特征和核糖体基因内转录间隔区（rDNA - ITS）序列构建系统发育树对该菌进行鉴定，菌株 XZ - S1与芸薹链格孢 Alternaria brassicae 在自举值99%相聚一群。生物学特性试验结果表明：该菌最适生长温度为25℃，最适生长 pH 值为6.5～7.5，淀粉为最佳碳源，蛋白胨为最佳氮源，马铃薯蔗糖琼脂培养基为最适生长培养基，马铃薯胡萝卜琼脂培养基为最适产孢培养基。