Phosphorylation‐dependent activation of the bHLH transcription factor ICE1/SCRM promotes polarization of the Arabidopsis zygote

• DOI: 10.1111/nph.20265
• Publication Date: 2024-11-15T05:14:59Z
• Authors: Houming Chen; Feng Xiong; Alexa‐Maria Wangler; Torren Bischoff; Kai Wang; Yingjing Miao; Daniel Slane; Rebecca Schwab; Thomas Laux; Martin Bayer
• Keywords: 570; 0303 health sciences; 03 medical and health sciences; Research; 500

Summary In Arabidopsis thaliana , the asymmetric cell division (ACD) of zygote gives rise to embryo proper and an extraembryonic suspensor, respectively. This process is controlled by ERECTA‐YODA‐MPK3/6 receptor kinase‐MAP kinase‐signaling pathway, which also orchestrates ACDs in epidermis. this context, bHLH transcription factor ICE1/SCRM negatively MPK3/6‐directed phosphorylation. However, it unknown whether regulatory module similarly involved zygotic ACD. We investigated function SCRM polarization analyzing effect loss‐of‐function alleles variants that cannot be phosphorylated MPK3/6, protein accumulation, target gene expression. Our results show has a critical acts parallel with known MPK3/6 WRKY2 activating WOX8. work further demonstrates activity early positively MPK3/6‐mediated Therefore, MAP kinase‐directed phosphorylation same fundamentally differs between epidermis, shedding light on type‐specific, differential regulation common signaling pathways.