山西省草地早熟禾白粉菌分离株BGP(TG)的鉴定及致病力分析

Identification and pathogenicity of Blumeria graminis f. sp.poae the BGP(TG) strain isolated from Poa pratensis infectedwith powdery mildew in Shanxi Province

【背景】草地早熟禾(Poa pratensis)是一种被广泛使用的兼具观赏性和设施性的冷季型草坪草,白粉病的发生严重降低了草地早熟禾的质量和使用年限。【目的】对山西农业大学温室草地早熟禾白粉病病原物进行分离、纯化、鉴定和致病力分析,为草地早熟禾白粉病的防治提供理论依据。【方法】采用形态特征观察、核糖体内源转录间隔区(ribosomal DNA internally transcribed spacer,rDNA-ITS)序列分析进行分离株BGP(TG)的鉴定;通过分生孢子密集抖落接种法测定BGP(TG)对23份草地早熟禾材料的致病力。【结果】草地早熟禾白粉菌分离株BGP(TG)分生孢子串生、无色、椭圆形,长和宽分别为(23.31-34.67)μm和(11.33-15.77)μm,成熟吸器为指状;rDNA-ITS序列分子发育分析结果表明分离株BGP(TG)与禾布氏白粉菌早熟禾专化型(Blumeria graminis f.sp.poae)聚于同一分支;BGP(TG)对23份草地早熟禾的致病力测定结果显示,白粉病发病率为49.47%-77.72%,病情指数为14.41-53.12;仅‘太行’草地早熟禾对BGP(TG)表现为中抗,‘应县’‘黑杰克’和‘浑源’草地早熟禾表现为中感,‘探险家’和‘奖品’草地早熟禾表现为极感,其余17个品种表现为高感,占比达73.91%。【结论】山西省草地早熟禾白粉菌分离株BGP(TG)的致病力较强,进一步挖掘‘太行’草地早熟禾的抗白粉病基因,对草地早熟禾抗白粉病育种工作具有重要意义。

[Background]Poa pratensis is a species of widely used ornamental and facility cold-season turfgrass.Powdery mildew caused by Blumeria graminis f.sp.poae seriously reduces the lawn quality and shortens the service life of P.pratensis.[Objective]To isolate,identify,and determine the pathogenicity of the isolate BGP(TG)and provide a theoretical foundation for the prevention and control of powdery mildew in P.pratensis.[Methods]BGP(TG)isolated from a greenhouse of Shanxi Agricultural University was identified based on the morphological characteristics and ribosomal DNA internally transcribed spacer(rDNA-ITS)sequence.The pathogenicity of the isolate was determined with 23 samples of P.pratensis.[Results]The conidiospores of the pathogen were in chains,colorless,and oval,with the size of(23.31−34.67)μm×(11.33−15.77)μm and finger-like mature haustoria.The phylogenetic analysis based on rDNA-ITS sequences showed that the BGP(TG)isolate and B.graminis f.sp.poae shared the same branch.The pathogenicity tests showed that the disease index ranged from 14.41 to 53.12,and the incidence ranged from 49.47%to 77.72%nine days after 23 samples of P.pratensis were inoculated with BGP(TG).Only the native species‘Taihang’in Shanxi Province showed moderate resistance to BGP(TG).‘Yingxian’,‘Black Jack’,and‘Hunyuan’showed moderate sensitivity,and‘Explorer’and‘Award’showed extreme sensitivity.The other 17 species showed high sensitivity,accounting for 73.91%.[Conclusion]The pathogenicity of BGP(TG)in Shanxi Province was strong.Mining the genes conferring resistance to powdery mildew from P.pratensis‘Taihang’will be of great significance for the breeding of P.pratensis with resistance to powdery mildew.