湖南永州奈李果实一种新病害的病原鉴定

Identification of pathogen causing new disease of Prunus salicina Lindl. var. cordata Y. He et J. Y. Zhang cv.younai fruits in Yongzhou, Hunan

【目的】明确危害湖南永州奈李果实新发生病害的病原物种类，为更好地识别并防控该病害提供理论依据。【方法】用常规分离方法对湖南永州奈李果园发病样品进行病原菌分离，通过形态学特征观察，ITS、TUB、CAL和ACT序列和系统发育进化树分析及致病性测定，对分离获得的病原菌进行鉴定。【结果】分离获得的病原菌形态学特征与大豆拟茎点霉（Phomopsislongicolla）一致；其ITS、TUB、CAL、ACT序列与P．10ngicolla同源性分别为98％、99％、99％和98％。室内人工接种病原菌3～5d后果实形成椭圆形至不规则形褐色病斑、后转腐烂等症状，与田间果实危害症状一致。【结论】初步确定危害湖南永州奈李果实的病原菌为PlongicollaYZ。

[Objective ]In order to provide theoretical basis for recognizing and controlling new disease, the pathogen causing new disease of Prunus salicina Lindl. var. cordata Y. He et J. Y. Zhang cv. younai from Yongzhou, Hunan was i- dentified. [Method]Using conventional isolation method, the pathogen was isolated from diseased fruits of P. salicina col- lected from orchard of Yongzhou, Hunan. Then, the pathogen was identified based on pathogenicity test, morphological characteristics observation, and analysis of rDNA-1TS, beta-tubulin（TUB）, calmodulin（CAL） and actin（ACT） sequences and phylogenetic tree. [ResultlThe morphological characteristics of pathogen were consistent with those of Phomopsis longicolla. ITS, TUB, CAL and ACT sequences analysis showed that the pathogen shared 98%, 99%, 99% and 98% ho- mology with P. longicolla, respectively. Furthermore, the disease symptoms were found on P. salicina fruits within 3-5 d after indoor artificial inoculation, such as first forming elliptic or irregular brown necrosis then rotting, which were in ac- cordance with those of fruits in the field. [Conclusion]The pathogen is identified as P. longicolla YZ, which can cause new disease of P. salicina.