March 13, 2014
Elucidation of the flow of information from pathogen recognition to defense response
Researchers from RIKEN CSRS and from The Sainsbury Laboratory in UK have shed light on the molecular-level mechanism by which plants rapidly produce reactive oxygen species (ROS) and ward off pathogens after recognizing an infection.
Researchers working collaboratively were exploring factors that form complexes with immune sensors, and identified the enzyme RBOHD (respiratory burst oxidase homolog D), which generates ROS. Upon detailed analysis of the flow of signaling from immune sensor to RBOHD, researchers discovered that the kinase BIK1 mediates phosphorylation and activation of RBOHD, inducing a protective response with the generation of ROS. Furthermore, the ROS generated by BIK1-mediated activation of RBOHD serves not only as a toxic factor for direct attack of pathogens, but also serves as a communication factor for closing the stomata, which is one of the main points of entry for pathogens.
These findings provide vital foundation knowledge for future research of signaling pathways of immune sensors. In addition, ROS generated through RBOH serve not only as a disease response, but also play an important role in organogenesis, environmental stress responses (drought, salt damage, high temperatures, injury, etc.) and responses to insect-pest; the newly discovered way RBOHD is activated is expected to contribute to an understanding of the molecular mechanisms of a wide variety of physiological responses in plants.
Molecular Cell doi:10.1016/j.molcel.2014.02.021
Y. Kadota, J. Sklenar, P. Derbyshire, L. Stransfeld, S. Asai, V. Ntoukakis, J. DG Jones, K. Shirasu, F. Menke, A. Jones, C. Zipfel,
"Direct regulation of the NADPH oxidase RBOHD by the PRR-associated kinase BIK1 during plant immunity".
Plant Immunity Research Group