Two E3 ligases promote cytokinin signalling by regulating NADPH oxidases activity in Arabidopsis (PI: Dr. Yiping Wang)
NADPH oxidases (NOX) are the enzymes that generate reactive oxygen species (ROS). In plants, NOX (also termed Rboh) have been reported to be involved in various physiological processes, such as cell growth, development and responses to environmental stresses. Cytokinin is one of the most important phytohormones regulating plants growth and development by promoting cell proliferation, differentiation and other cellular processes. Very few studies have been reported so far linking ROS and cytokinin signaling although both of them have been well-studied. Our previous work indicated that two E3 ligases PUB 2 and PUB 4 contribute to cytokinin responses. Recently, PUB2 and PUB4 were found to directly interact with NOX and is involved in ROS production in our lab. It is likely that PUB 2/4 might interact with Rboh proteins and ubiquitin them, resulting in modulation of the NADPH oxidases activity. We will test whether PUB 2/4 might regulate NOX activity through mono-ubiquitination and whether ROS production by such an action functions in cytokinin responses. Our study will provide new insights into roles of ROS in plant growth，development and stress responses.