Redox regulation of plant stem cell fate.

Despite the importance of stem cells in plant and animal development, the common mechanisms of stem cell maintenance in both systems have remained elusive. Recently, the importance of hydrogen peroxide (HO) signaling in priming stem cell differentiation has been extensively studied in animals. Here, we show that different forms of reactive oxygen species (ROS) have antagonistic roles in plant stem cell regulation, which were established by distinct spatiotemporal patterns of ROS-metabolizing enzymes. The superoxide anion (O2·-) is markedly enriched in stem cells to activate and maintain stemness, whereas HO is more abundant in the differentiating peripheral zone to promote stem cell differentiation. Moreover, HO negatively regulates O2·- biosynthesis in stem cells, and increasing HO levels or scavenging O2·- leads to the termination of stem cells. Our results provide a mechanistic framework for ROS-mediated control of plant stem cell fate and demonstrate that the balance between O2·- and HO is key to stem cell maintenance and differentiation.