Figure 10.

Model showing how COE2 regulates root development in response to nitrogen limitation. Under nitrogen limitation, once COE2 perceives the nitrogen limitation signal in leaves, production of NO regulated by NIA1/NIA2 is triggered. At the same time, COE2 is involved in the inhibition of chloroplast and leaf development in response to the nitrogen limitation signals. Under the conditions of nitrogen limitation, NO is produced in leaves and transported to roots to enhance the expression of TFs and development of lateral roots by COE2; alternatively, NO is directly produced in roots and then relies on COE2 to regulate the expression of TFs and the development of lateral roots.