Two-component systems involved in hyperosmotic signal transduction in Synechocystis sp. PCC6803

Abstract

Plants and microorganisms respond to osmotic changes by regulating the gene expression. We previously found that histidine kinase Hik33 acts as a sensor of the hyperosmotic stress in the cyanobacterium, Synechocystis sp. PCC 6803. In this study, we further searched for components involved in hyperosmotic signal transduction pathway in this organism by dot-blotting and DNA-microarray analysis to screen the knockout libraries of all histidine kinases and response regulators. The results showed that cells perceived and transduced the hyperosmotic signal by several two-component systems such as Hik33/Rre31, Hik33/Rre18, Hik34/Rre1 and Hik16/Hik41/Rre17 and Hik10/Rre3. These results suggested that cells utilize various two-component systems to cascade the hyperosmotic signal. Moreover, the pathway is not a simple two-component system as one histidine kinase sensor and one response regulator, but also includes the complex two-component systems.