NO means GO for pathogens

Plants and animals may share the same innate response to pathogens, according to a German study. Lipopolysaccharides (LPS), components of the bacterial cell wall, was found to induce a strong and rapid burst of nitric oxide, NO, in leaves and cultured cells of Arabidopsis thaliana. NO is toxic to bacteria, but the study showed that it also served as a signalling molecule to activate other defense pathways. LPS-induced NO-production depended on the gene AtNOS1 encoding NO synthase. Mutants defective in this gene failed to activate several defence related genes and had increased susceptibility to the pathogen Pseudomonas syringae. This suggests that LPS-induced NO production is an important part of the immune response in plants, as it is also known to be in mammals.

Source: Zeidler et al (2 November 2004) PNAS 101: 15811-15816