【摘要】 白粉病是海南黑皮冬瓜生产上最严重的病害之一。为弄清其病原和遗传进化关系,本研究采用形态观察、致病性测定、分子鉴定和生物信息学分析相结合的方法,对采自儋州、海口、文昌等地的黑皮冬瓜白粉病样进行了病原鉴定和遗传多样性分析。结果表明:病原菌形态上具有叉丝单囊壳(Podosphaera sp.)的典型特征。其分生孢子椭圆形,无色单胞,内含有明显的纤维丝;附属丝为菌丝状。在分子鉴定中,代表样品的ITS序列与NCBI数据库中苍耳叉丝单囊壳(Podosphaera xanthii)(登录号:JQ728480.1, KP980563.1, MH143487.1,KX369541.1和KX371257.1)的多条序列相似性达100%;与菊科白粉病菌(Podosphaera senecionis)(登录号:KY660807.1)等相似性小于97%;系统进化分析中,所有瓜类白粉病菌聚在一个分支上,遗传距离近,差异较小;与菊科白粉病菌等在不同分支上,遗传距离较远。结合形态、分子和遗传进化分析,将黑皮冬瓜白粉病的病原鉴定为苍耳叉丝单囊壳(Podosphaera xanthii)。本研究为冬瓜白粉病流行规律、成灾机理和抗病育种的研究提供了重要的技术支持。更多还原

【Abstract】 Powdery mildew was one of the most serious diseases in the production of wax groud in Hainan. In order to understand the pathogens of wax groud powdery mildew and their genetic diversity, in this study, the methods of morphological identification, pathogenicity determination, molecular identification and bioinformatics analysis were used to identify pathogen and analyze genetic diversity. Several samples of wax groud were collected from Danzhou, Haikou, Wenchang and so on. The results showed that the pathogen separation had typical morphological characteristics of Podosphaera sp.. The meristem was elliptical, colorless single cell, containing obvious fiber filaments; the attached silk was myceliform. In molecular identification, the ITS sequences of representative samples were similar to these sequences of Podosphera xanthii in the NCBI datdbase(Assession number of DQ728480.1, KP 980563.1, MH143487.1, KX369541.1, and KX371257.1) with similarity of 100%.Less than 97% of similarity with Podosphaera senecionis(Accession number of KY660807.1). In the phylogenetic analysis, all melon powdery mildew gathered on the same branch with the closer genetic distance, and the difference was smaller. They were clustered on the different branch of Podosphaera senecionis, with the farthest of genetic distance. Together with morphological characteristics, analysis of sequences and phylogentic, the pathogen of wax groud Powdery mildew was identified Podosphera xanthii. These research results provided important technical support for the research of epicemic law and pathogenesis of powdery mildew. It also provided technical support for the research of breeding against disease resistance.更多还原