Pseudomonas syringae is a rod shaped, Gram-negative

Gram-negative

Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...

 bacterium with polar flagella. It is a plant pathogen which can infect a wide range of plant species, and exists as over 50 different pathovar

Pathovar

A pathovar is a bacterial strain or set of strains with the same or similar characteristics, that is differentiated at infrasubspecific level from other strains of the same species or subspecies on the basis of distinctive pathogenicity to one or more plant hosts.Pathovars are named as a ternary or...

s, all of which are available to legitimate researches via international culture collections such as the NCPPB, ICMP, and others. Many of these pathovars were once considered to be individual species within the Pseudomonas genus, but molecular biology

Molecular biology

Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

 techniques such as DNA hybridization have shown these to in fact all be part of the P.