Pseudomonas syringae pathovars

Pseudomonas syringae is one of the best studied plant pathogens. P. syringae pathovars exhibit unique host specificities by infecting different kinds of plants, causing huge economic losses. Studies on the molecular interactions between P. syringae pathovars and plants have made huge contributions towards our understanding of the plant immune system and microbial pathogenicity. Flagellin, lipopolysaccharide (LPS), extracellular polysaccharides (EPS) and EF-Tu from P. syringae are recognized by their receptors/coreceptors FLS2-BAK1, LORE, and EFR-BAK1, respectively, to activate immunity triggered by pathogen-associated molecular patterns (PAMPs). P. syringae relies on cell-wall-degrading enzymes secreted through the type II secretion system (T2SS), type III effectors delivered into plant cells by the type III secretion system (T3SS), and toxins, such as coronatine, to cause diseases. Plants have developed resistance (R) proteins to recognize some of these effectors or avirulence proteins, inducing the hypersensitive response. Ice-nucleation-active (INA) proteins from P. syringae, which can initiate ice formation, have been used to produce artificial snow.