海南火龙果叶斑病病原鉴定与系统进化分析

Pathogenic Identification of Dragon Fruit Leaf Spot Disease and Phylogenetic Analysis in Hainan

为了明确海南火龙果叶斑病的病原及为后续的防治提供技术支持,本研究从海南海口、临高、陵水、三亚、儋州、琼海等地采集病样123份,采用常规组织分离纯化、形态学观察、致病性测定和ITS序列分析,鉴定了火龙果叶斑病的病原。结果表明:形态上具有典型的拟茎点霉(Phomopsis sp.)特征;而ITS序列分析上,代表菌株43A1和43A2与NCBI数据库中Phomopsis sp.179GP/T (登录号:GQ352484.1)和Phomopsis sp.131AM/T (登录号:GU066693.1)均在99%以上;系统发育树上,43A1、43A2与Phomopsis sp.131AM/T和Phomopsis sp.179GP/T聚在同一分支上面,遗传距离最近。说明海南火龙果叶斑病的病原为火龙果拟茎点霉Phomopsis pitaya,这是国内首次在火龙果上发现该病原菌。研究结果为弄清火龙果叶斑病流行规律、致病机理等具有重要的意义。

In order to identify the pathogen of dragon fruit leaf spot disease and provide technical support for the subsequent control, 123 disease samples of dragon fruit leaf were collected from dragon fruit bases of Haikou, Lingao, Lingshui, Shanya, Danzhou and Qionghai. The pathogen of dragon fruit leaf spot disease was studied by routine tissue separation and purification, morphological identification, pathogenicity determination and molecular biology identification. The results showed that the leaf spot of dragon fruit has typical characteristics of Phomopsis sp. The ITS sequences of 43A1 and 43A2 were similar to those of Phomopsis sp. 179GP/T （Genbank NO,GQ352- 484.1） and Phomopsis sp. 131 AM/T （Genbank NO.GU066693.1） in the NCBI database by more than 99%. By the phylogentic analysis, 43A1 and 43A2 were clustered on the same branch of several sequences of Phomopsis sp. 131 AM/T and Phomopsis sp. 179GP/T. And the genetic distance was closest. It showed that the pathogen of dragon fi-uit leaf spot disease was Phomopsis sp. in Hainan. This is the first time to find the pathogen on dragon fruit in our country. These research results had great significance to find out the epicemic law and Dathogenesis ofthe leaf spot disease of dragon fruit.