Low nitrogen conditions accelerate flowering by modulating the phosphorylation state of FLOWERING BHLH 4 in <i>Arabidopsis</i>
Miho Sanagi, Shoki Aoyama, Akio Kubo, Lu Yu, Yasutake Sato, Shogo Ito, Mitsutomo Abe, Nobutaka Mitsuda, Masaru Ohme‐Takagi, Takatoshi Kiba, Hirofumi Nakagami, Filip Rolland, Junji Yamaguchi, Takato Imaizumi, Takeo Sato
Abstract
Significance Nitrogen availability has a large impact on plant biomass and crop production. Both depletion and excessive application of nitrogen affect crop yields and quality and disturb important ecosystems. Thus, understanding the mechanisms by which nitrogen regulates developmental transitions affecting reproduction, such as flowering, is important to sustainably improve crop yields. Our study identified FBH4 as a key transcription factor mediating nitrogen-responsive flowering in Arabidopsis . Nitrogen levels control the FBH4 phosphorylation state that modulates transcriptional activity as a molecular switch to induce flowering. The cellular fuel sensor SnRK1 catalyzes FBH4 phosphorylation and negatively regulates florigen levels in high nitrogen conditions. These findings will enable new molecular breeding strategies to achieve better crop yields through optimized flowering time under different nitrogen conditions.