丁香假单胞菌在3种苔藓中的致病性研究

Research on the Pathogenicity of Pseudomonas syringae to Three Moss Species

【目的】探究细菌性病原菌丁香假单胞菌(Pseudomonas syringae)对2种荒漠耐干苔藓以及1种模式苔藓的致病性,为苔藓—病原菌互作模式的构建提供参考,并为抗病基因的筛选提供思路。【方法】选用2种荒漠耐干苔藓——齿肋赤藓(Syntrichia caninervis)和银叶真藓(Bryum argenteum)以及1种苔藓模式种——小立碗藓(Physcomitrella patens),通过形态学观察和植物抗病指标检测分析丁香假单胞菌在3种苔藓中的致病性以及3种苔藓的响应。【结果】丁香假单胞菌侵染苔藓后,随着接种时间的增加,苔藓细胞死亡量增加,死亡细胞多集中在病害发生区域。过氧化氢(H2O_(2))和超氧阴离子原位染色结果表明:丁香假单胞菌入侵会造成3种苔藓发生免疫反应,且随着接种时间的增加,H2O_(2)和超氧阴离子产生量增多,并以发生病斑及萎蔫植株中的含量最高。荧光定量PCR结果表明:3种苔藓体内的丁香假单胞菌病原菌数量与接种时间呈正相关。【结论】供试的3种苔藓可被丁香假单胞菌成功侵染,表现为出现细菌性病斑、茎秆褐化以及发生褪绿现象。研究结果为后续进一步探讨极端干燥环境下植物—病原菌的互作机制提供了参考。

[Purpose]To investigate the pathogenicity of Pseudomonas syringae to two desiccation tolerant mosses and one type of model moss,providing reference for the establishment of moss-pathogen interaction mechanism and an idea for screening of resistance genes.[Methods]Two desiccation tolerant mosses,Syntrichia caninervis and Bryum argenteum,and one model moss species,Physcomitrella patens,were selected to study the pathogenicity of P.syringae in three mosses and the pathogenicity response of the three mosses,by morphological observation and plant disease resist-ance index monitoring.[Results]The number of moss cell death increased after infection of P.syr-ingae,and most of the dead cells were concentrated in infection area.The results of hydrogen perox-ide(H2O2)and superoxide anion in situ staining showed that the invasion of P.syringae could cause the immune reaction of three mosses,and the production of H2O2 and superoxide anion increased with the time of inoculation,the highest content was found in diseased spot and wilting plant.The qPCR results showed that the number of P.syringae in the three mosses were positively correlated with the inoculation time.[Conclusion]These three experimental mosses are successfully infected by P.syr-ingae,the specific manifestations are the appearance of bacterial venereal spots,browning and chlorosis of stems.The results provide a reference for further study of plant-pathogen interaction mechanism under extreme drying environment.