From DrugPedia: A Wikipedia for Drug discovery
Pseudomonas syringae is a rod shaped, Gram-negative bacterium with polar flagella. A plant pathogen which can infect a wide range of plant species, and exists as over 50 different pathovars. It tests negative for arginine dihydrolase and oxidase activity, and forms the polymer levan on sucrose nutrient agar.
 Surface Characteristics
In cell wall O-polysaccharides of the LPS consists of tetra- and tri-α-D-rhamnose repeats in the backbone [-3)D-Rha(α1->3)D-Rha(α1-->2)D-Rha(α1->2)D-Rha(α1] and [3)D-Rha(α1-->3)D-Rha(α1-->2)D-Rha(α1-]
 Pathogenic Activity
It is responsible for the surface frost damage in plants, exposed to the environment. P. syringae can cause water to freeze at temperatures as high as −1.8°C, but strains causing ice nucleation at lower temperatures (down to −8°C) are more common. The freezing causes injuries in the epithelia and makes the nutrients in the underlying plant tissues available to the bacteria.