Pathogenesis of the Human Opportunistic Pathogen Pseudomonas aeruginosa PA14 in Arabidopsis

The human opportunistic pathogen Pseudomonas aeruginosa strain PA14 is a multihost pathogen that can infect Arabidopsis. We found that PA14 pathogenesis in Arabidopsis involves the following steps: attachment to the leaf surface, congregation of bacteria at and invasion through stomata or wounds, colonization of intercellular spaces, and concomitant disruption of plant cell wall and membrane structures, basipetal movement along the vascular parenchyma, and maceration and rotting of the petiole and central bud. Distinctive features of P. aeruginosa pathogenesis are that the surface of mesophyll cell walls adopt an unusual convoluted or undulated appearance, that PA14 cells orient themselves perpendicularly to the outer surface of mesophyll cell walls, and that PA14 cells make circular perforations, approximately equal to the diameter of P. aeruginosa, in mesophyll cell walls. Taken together, our data show that P. aeruginosa strain PA14 is a facultative pathogen of Arabidopsis that is capable of causing local and systemic infection, which can result in the death of the infected plant.

人类机会致病菌铜绿假单胞菌（Pseudomonas aeruginosa）菌株PA14是一种可侵染拟南芥（Arabidopsis）的多宿主致病菌。本研究发现，该菌株在拟南芥中的致病过程包含以下环节：附着于叶片表面、细菌聚集于气孔或伤口处并侵入其中、定殖于细胞间隙、伴随破坏植物细胞壁与膜结构、沿维管薄壁组织向基性移动，以及叶柄与中央芽发生软腐腐烂。铜绿假单胞菌致病过程的显著特征包括：叶肉细胞壁表面呈现异常卷曲或波纹状外观、PA14菌体垂直排布于叶肉细胞壁外表面，以及PA14菌体可在叶肉细胞壁上形成直径与该菌自身尺寸相当的圆形穿孔。综上，本研究数据表明，铜绿假单胞菌菌株PA14是拟南芥的兼性致病菌，可引发局部与系统性侵染，最终导致受侵染植株死亡。