【作者】 李亚利；

【导师】 陈秀蓉；

【作者基本信息】 甘肃农业大学 ， 植物病理学， 2006， 硕士

【摘要】 近年来,甜瓜细菌性叶斑病在新疆发生普遍,危害严重,给瓜农造成极大的损失。据2004～2005年调查,在甘肃省河西地区的西瓜、甜瓜地中有零星发生,由于该病症状与西瓜细菌性果斑病在叶片上的症状很相似,认为可能是西瓜细菌性果斑病。因此,2004～2005年对采集到的病叶经分离纯化得到纯菌株,测定了该菌株的致病性和寄主范围,用16S rDNA分子生物学方法进行了鉴定,并利用PCR技术对病瓜及病瓜种子带西瓜细菌性果斑病菌的情况进行了检测,现将结果报道如下:1甜瓜细菌性叶斑病菌Ps1、Ps2的致病性及寄主范围测定从甘肃河西、新疆阿勒泰甜瓜上分离获得的17种菌中,选择了具有代表性的2种菌株(编号Ps1、Ps2)和西瓜细菌性果斑病的标准菌株,测定其致病性和寄主范围,结果表明:甜瓜细菌性叶斑病菌与西瓜细菌性果斑病菌的寄主一致,即除可侵染葫芦科植物西瓜、黄瓜、甜瓜、西葫芦、苦瓜、冬瓜、瓠瓜、丝瓜等外,还能侵染番茄、玉米、茄子、辣椒、菜豆等非葫芦科植物,2细菌性叶斑病菌16SrDNA分子鉴定对分离到的甜瓜细菌性叶斑病的病原菌Ps1、Ps2和西瓜细菌性果斑病的标准菌株,经DNA提取,PCR扩增16S rDNA基因片断后测序,其基因序列与GenBank中报告的已知序列比较,结果表明Ps1、Ps2与已报道的Pseudomonas syringae(登录号为AF094749)、标准菌株与Acidovorax avenae subsp. citrulli(登录号为AF137505)序列同源性高达99%,基本确定了这三个菌株在系统发育学中的地位,初步确定当地甜瓜细菌性叶斑病菌主要是丁香假单胞杆菌Pseudomonas syringae (Van Hall)。3西瓜细菌性果斑病菌的PCR检测2004～2005年从甘肃、新疆、内蒙等西甜瓜主产区收集到的认为染有西瓜细菌性果斑病的甜瓜、西瓜果实和种子25份,应用西瓜细菌性果斑病菌的特异性基因序列,进行PCR检测,结果只有西瓜细菌性果斑病菌的标准菌株(Acidovorax avenae subsp.citrulli)在360bp的位置出现了特异性的条带,其余待测菌株都没有此条带产生,说明通常根据症状诊断的西瓜细菌性果斑病并不是细菌性果斑病菌为害所致,初步确定2004～2005年在甘肃和新疆甜瓜主产区很少或没有西瓜细菌性果斑病的发生。更多还原

【Abstract】 Bacterial spot of muskmelon leaves(Pseudomonas syringae), widely dispersed in Xinjiang was a harmful disease, which brought about enormous economic losing to peasants. Based on investigation in Hexi, Gansu province from 2004 and 2005, it was found that the disease can be observed accasionally on watermelon and muskmelon,and it was likely to be Bacterial blotch of watermelon because of the symptom of the disease on leaves were similar to Bacterial blotch of watermelon,so pathogenic bacteria were isolated and purified from disease leaves for further study in 2004 and 2005.Molecular biology 16SrDNA was used to identify pathogen and Pathonenicity and host range were also examined in this paper. In addition , PCR test was also used to examine whether illness melon and seeds carried Acidovorax avenae subsp.citrulli or not .The results were as following:1 Test of pathonenicity and host range of Bacterial Spot of Muskmelon LeavesTwo typical pathogenic strains Ps1、Ps2 were selected from Seventeen bacterial strains isolated from watermelon and muskmelon in Hexi ,Gansu provice and Aletai in Xinjiang, for Pathogenicity test and host range with standard strain of Bacterial blotch of watermelon in contrast. The results showed that the bacteria and the standard strain of Bacterial blotch of watermelon had the same host range,all of them not only infected with watermelon、cucumber、muskmelon、pumpkin、balsam pear、wax-gourd、calabash gourd、vegetable sponge,etc gourd plants,but also tomato、corn、eggplant、pepper、bean.2 16SrDNA Identification of Pathogen of Bacterial Spot of Muskmelon LeavesDNA of pathogenic bacteria Ps1、Ps2 and standard strain of Bacterial blotch of watermelon were extracted for PCR amplification and sequencing. By comparing these sequences with known sequences in GenBank,it was found that the gene更多还原