Submitted to: Chemistry and Biology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/2/2008
Publication Date: 2/4/2008
Citation: Johnson,, E.G., Sparks,, J.P., Dzikovski,, B., Crane,, B.R., Gibson, D.M., Loria,, R. 2008. Plant pathogenic Streptomyces species produce nitric oxide synthase-derived nitric oxide in response to host signals. Chemistry and Biology. 15(1):43-50. Interpretive Summary: Plant-pathogenic Streptomyces cause “scab” diseases on potato tubers, as well as other root crops, due to the presence of a phytotoxin produced in part by the enzyme nitric oxide synthase. This enzyme is known to produce free nitric oxide (NO) in animals and plants. In this study, we were able to show that the plant pathogenic Streptomyces bacteria are able to produce free NO at the plant host surface in response to cellobiose, a plant cell wall-derived component. This study is the first report demonstrating the production of free NO by these bacteria, suggesting that it may play an important role in host-pathogen interactions.
Technical Abstract: Nitric oxide (NO) is a potent intercellular signal for defense, development and metabolism in animals and plants. In mammals, highly regulated nitric oxide synthases (NOSs) generate NO. NOS homologs exist in some prokaryotes, but direct evidence for NO production by these proteins has been lacking. Here we demonstrate that a NOS in plant-pathogenic Streptomyces species produces diffusible NO. NOS-dependent NO production increased in response to cellobiose, a plant cell wall component, and occurred at the host-pathogen interface, demonstrating induction by host signals. These data are the first to document in vivo production of NO by prokaryotic NOSs and to implicate pathogen-derived NO in host-pathogen interactions. NO may serve as a signaling molecule in other NOS-containing bacteria, including medically and environmentally important organisms Bacillus anthracis, Staphlococcus aureus, and Deinococcus radiodurans.