草莓根部侵染草莓炭疽菌的致病动态变化过程

Pathogenic Process of Strawberry Roots Infected by Colletotrichum fragariae

为了从组织学和细胞学水平上了解草莓炭疽菌(Colletotrichum fragariae)病原菌致病机理及其与寄主的互作机制,通过草莓炭疽菌分生孢子液接种侵染健康草莓幼苗根,在荧光显微镜下观察病原菌的侵染过程,研究草莓根部浸染草莓炭疽菌的致病性。结果表明,接种12 h,95%的分生孢子萌发;接种24 h,69%芽管顶端产生附着胞或附着枝并形成侵入钉开始侵染根表皮细胞;接种48 h,产生大量菌丝并纠结成网状;接种4 d,少量的根尖开始变褐;接种9 d,整个根系几乎变为黑褐色,产生少量分生孢子盘;接种13 d,侵染菌丝扩展到主轴根微管柱,新的分生孢子产生,完成一个侵染循环;接种20 d,侵染菌丝入侵到达叶柄和花茎;接种41 d,侵染菌丝扩散到叶柄表面并侵染叶柄腺毛;接种55 d,侵染菌丝入侵到达叶片并侵染叶片腺毛,组织细胞开始崩解死亡,叶片上形成典型的炭疽病病斑。[结论]:C.fragariae能通过根侵染到整株植株,属于系统性侵染。

In order to know the pathogenesis of Colletotrlchumfiagariae and the interaction mechanism with the hosts at levels of histology and cytology, the healthy strawberry seedlings were inoculated with conidia of pathogen C. fragariae by root dipping in conidia suspension. The pathogen infection process was observed by fluorescence microscope at different time points after inoculation. Results： After 12 h,95 % of conidia germinated, about 69 % conidia formed classical appreasoria and hyphopodia, and infection pegs began to penetrate the epidermul cells of roots at 24 h, and by 48 h, the hyphae had extensively colonized and formed a network around the roots. By four days, several plants had developed slightly brown discolouration at root tips, by nine days, almost all roots had developed largely black and/or brown diseoloura- tion and formed a spot of acervulus. By 13 days, hyphae had invaded to the vascular bundle on the main roots and formed the new conidia, completing the disease cycle. By 20 days, hyphae had invaded petioles and rachis above ground, and were found on the petioles surface and glandular hairs of petioles at 41 d. By 55 d hyphac had invaded the leaves and their glandular hairs. Typical anthracnose disease spots were found on the leaves, which had begun to decompose. Conclusion： subsequent to inoculation, the C. fiagariae infection can spread across the entire strawberry plants via the roots, which is indicative of a systemic infection.