UV RESISTANCE LOCUS 8 (UVR8) is an ultraviolet-B (UVB) radiation photoreceptor that mediates light responses in plants. How plant UVR8 acts in response to UVB light is not well understood. Here, we report the identification and characterization of the Arabidopsis WRKY DNA-BINDING PROTEIN 36 (WRKY36) protein. WRKY36 interacts with UVR8 in yeast and Arabidopsis cells and it promotes hypocotyl elongation (下胚轴伸长) by inhibiting HY5 transcription. Inhibition of hypocotyl elongation under UVB requires the inhibition of WRKY36. WRKY36 binds to the W-box motif of the HY5 promoter to inhibit its transcription, while nuclear localized UVR8 directly interacts with WRKY36 to inhibit WRKY36–DNA binding both in vitro and in vivo, leading to the release of inhibition of HY5 transcription. These results indicate that WRKY36 is a negative regulator of HY5 and that UVB represses WRKY36 via UVR8 to promote the transcription of HY5 and photomorphogenesis (光形态建成). The UVR8–WRKY36 interaction in the nucleus represents a novel mechanism of early UVR8 signal transduction in Arabidopsis.

通讯：刘宏涛 (http://www.sippe.ac.cn/cp1-8_PI.asp?id=24)

研究方向：以拟南芥和玉米为对象，围绕光信号调控植物发育的分子机制，光信号传递的机制，及光信号转导与其他内外源信号的交叉整合展开植物分子发育研究。实验室网址：http://lht.sippe.ac.cn

Journal: Nature Plants

Published online: 29 January, 2018