[P4] Crop Genetics and Physiology

[P4-41] CO₂-Responsive CCT Protein Interacts with 14-3-3 Proteins and Regulates the Expression of Starch Synthesis-Related Genes

*Nominated for Presentation Awards

^○Fumihiro Miyagawa, Naoki Shibatani, Aiko Koudou, Daisuke Sasayama, Tomoko Hatanaka, Tetsushi Azuma, Hiroshi Fukayama (Graduate School of Agricultural Science, Kobe University, Japan)

CO₂-responsive CCT protein (CRCT) is a positive regulator of starch synthesis-related genes such as ADP-glucose pyrophosphorylase large subunit 1 and starch branching enzyme I particularly in the leaf sheath of rice (Oryza sativa L.). RNA-seq analysis and subsequent RT-qPCR analysis showed that sucrose treatment induced the expression of CRCT, which in turn induced starch synthesis-related genes in WT. However, this induction did not occur in CRCT knock out mutants. A chromatin immunoprecipitation (ChIP) using a FLAG-CRCT overexpression line and subsequent qPCR analyses showed that the 5'-flanking regions of some starch synthesis-related genes were enriched by ChIP, indicating that CRCT can bind to the promoter regions of these genes. A bimolecular fluorescence complement (BiFC) assay revealed that CRCT interacts with a 14-3-3 protein in the nucleus. These results suggests that CRCT responds to sugar and regulates starch synthesis by directly binding to the promoter region of starch synthesis-related genes and interacting with 14-3-3 protein.