佩兰白粉病的病原菌鉴定

Identification of Herba eupaatorii Fortunei Powdery Mildew

以发病的佩兰叶片为试材,采用形态学、致病性、分子系统学鉴定方法对该地区的佩兰白粉病病原菌进行研究,以期探明河南商丘地区的佩兰白粉病病原菌的系统进化关系,为其防治提供理论依据。结果表明:该白粉菌分生孢子透明,圆形或椭圆形,有明显的纤维体,大小为(18~27)μm×(15~22)μm,分生孢子梗直立、圆柱形、简单无分枝,大小为(112~180)μm×(9~12)μm,分生孢子形成在分生孢子梗上,串生,4~6个。没有观察到病原菌的子囊壳。病原菌接种叶片与自然状态发病叶片的病症相似,均为不定形的污白色斑。对核糖体DNA内转录间隔区(ITS)序列进行PCR扩增、测序获得565 bp的目的片段(Gen Bank登录号:JX546297),在Gen Bank上进行比对分析,与Podosphaera fusca序列同源性为100%,初步鉴定该病原菌为棕丝单囊白粉菌(Podosphaera fusca)。

Herba eupaatorii Fortunei leaves infected by the powdery mildews were used as materials.The pathogen of H.eupaatorii Fortunei powdery mildew was analyzed by morphological,etiological and molecular systematic identification.In order to make clear the phylogenetic evolution relationships of powdery mildew detected in Herba eupaatorii Fortunei in Shangqiu of Henan in China and supply reference for its control.The results showed that the primary conidia of the fungus were ovality or subspherical,measuring （18-27）μm×（15-22）μm.Long unbranched germ tube was unilateral lateral germination from the ends of conidia.Conidiophores was cylindrical,simple unbranched,composed of a basal cell with swollen base and 3 to 6 barrel-shaped conidia formed in chains,measuring （112-180）μm×（9-12）μm.Mycelial appressorium showed a nipple-shaped.Chasmothecia were not observed in the collected samples.Pathogenicity of inoculated leaves had no differences with leaves in natural station of amorphous dirt white patch.Internal transcribed spacer （ITS） sequence of its ribosomal DNA was amplified by PCR and sequenced to obtain the 565 bp target fragment （GenBank number：JX546297）,comparison with sequences in the GenBank database revealed that the ITS sequence showed 100% homology with the sequence of Podosphaera fusca on Calendula officinalis （Accession No.AB525914） and Syneilesis palmata （Accession No.AB040349）.The ITS sequence analysis further verified that the causal agent of the powdery mildew on H.eupaatorii Fortunei was Podosphaera fusca.