白三叶草叶片感染白粉病的细胞生理变化及其病原鉴定  

Pathogen identification and cell physiological changes of Trifolium repens leaves infected with powdery mildew

作　　者：杨凯[1] 史娟[1] 袁玉涛 王立婷 YANG Kai;SHI Juan;YUAN Yu-tao;WANG Li-ting(College of Agronomy,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学农学院,宁夏银川750021

出　　处：《草业学报》2021年第10期92-104,共13页Acta Prataculturae Sinica

基　　金：宁夏大学草学一流学科建设项目(NXYLXK2017A01)资助。

摘　　要：为了揭示白三叶草和白粉菌互作的细胞学机制,明确白三叶草白粉菌的分类地位,为牧草抗病育种和科学防控提供依据。采用光学显微镜和透射电镜技术观察了白粉菌侵入白三叶草叶片感染白粉病的细胞生理特征。通过传统形态学和ITS序列分析对白三叶草白粉病病原菌进行了鉴定,采用水琼脂玻片法观察了病原菌分生孢子萌发特性。结果表明,白粉菌在白三叶草表皮细胞和保卫细胞交界处直接侵入,菌丝侵入表皮细胞壁与寄主接触部分的胞壁组织被降解且颜色加深,对应的细胞内侧产生大量胞壁沉积物,细胞壁不再完整气孔通道变形,保卫细胞发生质膜分离;进入表皮细胞的吸器被寄主质膜包围形成交界面,栅栏组织细胞内叶绿体肿胀,由椭圆形变为近球形聚集,淀粉粒由长条形变为椭圆形,嗜锇颗粒增多。接种到叶片的分生孢子4 h萌发长出初生芽管,10 h形成附着胞,12 h附着胞一侧形成侵染钉,48 h次生菌丝形成,96 h时形成大量菌丝并分化出成熟的分生孢子梗,叶片显症;144 h时分生孢子梗分化出2~3个分生孢子,顶端最先成熟,168 h时粉层扩展至叶片的2/3,240 h时达到90%以上,且粉层加厚,叶片卷曲。依据分生孢子的形态,结合ITS序列鉴定,将宁夏地区白三叶草白粉病的病原菌鉴定为豌豆白粉菌。该菌在25℃、pH为7.0时生长最好,光照条件有利于分生孢子萌发。This experiment investigated the cytological mechanism of Trifolium repens and powdery mildew interaction,clarified the classification status of powdery mildew infecting T.repens,and provided information for breeding disease-resistant clover varieties and scientifically directed prevention and control of forage fungal pathogens.Optical and electron microscopy methods were used to observe the changes to cellular physiological characteristics caused by pathogens invading T.repens.The pathogen was identified as Erysiphe pisi based on traditional observation of morphological characteristics and sequence analysis of rDNA-ITS(ribosomal RNA internal transcribed spacer).The water agar slide method was used to observe conidial germination characteristics of E.pisi.The results showed that E.pisi directly invaded the epidermal cells of T.repens at the junction of epidermal cells and stomatal guard cells,resulting in degradation and darkening of color in the cell wall tissue of at the location where the hypha invaded the cell wall.A large quantity of cell wall deposits were produced inside the corresponding cells.After the cell wall was no longer intact,the stomatal channel deformed to cause plasma membrane separation of the guard cells.The haustorium that invaded the epidermal cell was surrounded by the host plasma membrane to form an interface.The chloroplasts in the palisade tissue cells swelled,changing from elliptical to nearly spherical and clustering,starch grains were changed in shape from elongated to elliptical,and osmophilic particle numbers increased.The conidia inoculated on the leaf germinated and grew primary bud tubes within 4 hours post-inoculation(hpi),formed mature appressoria in 10 hpi,formed infection pegs after 12 hpi,and secondary hyphae formed after 48 hpi.Germ tubes of abundant branches differentiated into hyphae and produced mature conidiospore after 96 hpi.At the same time leaves showed symptoms,the conidiophore differentiated into 2 to 3 conidia at 144 hpi,the top matured first,and the powder laye

关 键 词：白三叶草 白粉病 超微结构 病原菌鉴定 生物学特性 

分 类 号：S435.4[农业科学—农业昆虫与害虫防治]