Pseudomonas syringae

Pseudomonas syringae is rod-shaped, Gram negative bacterium. It is a plant pathogen. The bacterium can cause disease in many different plants. There are many variants, called pathovars. They are specialized to infect different plants. 

The bacterium can live as an epiphyte on the plant surface. It only causes disease once it is able to enter the plant cells. The bacterium enters the plant via wounds or natural openings like stomata. Once inside the plant tissues the bacteria multiply and cause leaf spots and cankers.

Examples of diseases caused by Pseudomonas syringae (P. s) include

  attacks horse chestnut trees causing horse chestnut bleeding canker
  attacks soybean Glycine max, causing bacterial blight of soybean.
  causes halo blight of beans.
  attacks cherry and plum causing bacterial canker.
This bacterium has been well studied as it is a useful model organism as well as an economically important plant pathogen.

 References 

Category:Gram-negative bacteria