观赏海棠干腐病病原菌鉴定

Identification of the Pathogen Causing Valsa Canker of Malus Crabapple

从观赏海棠干腐病病斑处分离纯化病原菌,采用柯赫氏法则对从病原菌进行验证,通过形态学结合ITS序列的系统发育分析鉴定确定病原菌种名,得到观赏海棠干腐病相关病原菌ZWY0501、ZWY0502(登录号:MG554650、MG554651),分离频率分别为55.36%、42.86%。2株孢子均无色,香蕉形或椭圆形,(3.13~5.51)μm×(1.19~1.89)μm。ITS系统发育树中,2株约590bp菌株与已登录的苹果腐烂病病株(Valsamali,登录号为:KP337612)同源性最高,最大相似率达到99%。形态学及ITS序列的系统发育分析鉴定ZWY0501、ZWY0502均为苹果黑皮腐壳菌(Valsamali),其为观赏海棠树皮腐烂病病原。研究结果为该病害的控制奠定了科学基础。

The objective of the present study was to isolate,purify and identify the pathogen from Malus crabapple valsa canker.The pathogen isolates were obtained from tissue lasions of valsa canker on crabapple tree trunks and confirmed via Koch s postulates,then they were identified on the basis of anamorphic morphology and rDNA Internal Transcribed Spacer (ITS) sequences.The two isolates,obtained from the Malus crabapple,were numbered as ZWY0501 and ZWY0502 (ncbi GenBank ID:MG554650、MG554651),the isolation frequency of which were 55.36% and 42.86%,respectively.Conidia of both isolates were hyaline,banana-shaped or elliptic,with sizes of 3.13-5.51×1.19-1.89 μm.A same ITS sequence of about 590 bp was obtained from the two isolates ZWY0501 and ZWY0502 and it shared a maximum semilarity of 99% with that of Valsa mali .Phylogenic analysis showed that the two isolates were clustered in the same clade with Valsa mali (GenBank ID:KP337612) but were separated in different degrees from other species in the dendrogram.Based on anamorphic morphology and rDNA internal transcribed spacer (ITS) sequences,the pathogen was identified as Valsa mali .The results of the study would provide scientific basis for selecting target fungicides and resistant crabapple varieties for controlling the disease.