欧美杨溃疡病菌在侵染寄主过程中的动态变化1）

摘要

We quantified bacterial population of Lonsdalea quercina in Populus×euramericana‘Zhonglin 46’ and disease symp-tom occurrence in the infection process of the pathogen by using real-time PCR and histopathology.The bacterial accumula-tion in number within Poplar branch bark tissue was detected at 3-day post-inoculation (dpi), while no disease symptom-soccurred.Then, the bacterial density within Poplar increased significantly with some cells in cortical layer broken, initial symptom occurred 5 dpi.Bacterial numbers reached a peak and maintained a high population 9-16 dpi, when the cell in the phloem was broke seriously, and parenchyma cells were disaggregated.The plants displayed severe disease symptoms. Therefore, real-time PCR assays can be used to quantify the pathogen in infected plant tissues.%采用Real－time PCR和病理组织切片相结合的方法，分析了欧美杨溃疡病病原菌（ Lonsdalea quercina subsp．populi）侵染欧美杨（ Populus×euramericana‘zhonglin46’）后不同时间的种群量及其变化。结果表明：接种3d后植株内己有一定的菌量积累，从结构上看，对植物尚未造成明显的伤害。但从接种第5天开始，菌量明显增加，部分细胞破裂，植株显症。接种9～15 d，菌量增加到峰值，并进入稳定期，韧皮部组织细胞破裂明显，薄壁细胞解离，植株显症严重。应用Real－time PCR分子定量法可直接对欧美杨植株体内的病原菌进行动态定量研究。