Modulation of starch synthesis in Arabidopsis via phytochrome B-mediated light signal transduction  

作　　者：Qingbiao Shi Ying Xia Na Xue Qibin Wang Qing Tao Mingjing Li Di Xu Xiaofei Wang Fanying Kong Haisen Zhang Gang Li 

机构地区：[1]National Key Laboratory of Wheat Improvement,College of Life Sciences,Shandong Agricultural University,Tai'an 271018,China [2]National Key Laboratory of Wheat Improvement,College of Agronomy,Shandong Agricultural University,Tai'an 271018,China

出　　处：《Journal of Integrative Plant Biology》2024年第5期973-985,共13页植物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(32270263);the Shandong Provincial Natural Science Foundation(ZR2022QC095,ZR2020MC023,ZR2022MC019).

摘　　要：Starch is a major storage carbohydrate in plants and is critical in crop yield and quality.Starch synthesis is intricately regulated by internal metabolic processes and external environmental cues;however,the precise molecular mechanisms governing this process remain largely unknown.In this study,we revealed that high red to far-red(high R:FR)light significantly induces the synthesis of leaf starch and the expression of synthesis-related genes,whereas low R:FR light suppress these processes.Arabidopsis phytochrome B(phyB),the primary R and FR photoreceptor,was identified as a critical positive regulator in this process.Downstream of phyB,basic leucine zipper transcription factor ELONGATED HYPOCOTYL5(HY5)was found to enhance starch synthesis,whereas the basic helix-loop-helix transcription factors PHYTOCHROME INTERACTING FACTORs(PIF3,PIF4,and PIF5)inhibit starch synthesis in Arabidopsis leaves.Notably,HY5 and PIFs directly compete for binding to a shared G-box cis-element in the promoter region of genes encoding starch synthases GBSS,SS3,and SS4,which leads to antagonistic regulation of their expression and,consequently,starch synthesis.Our findings highlight the vital role of phyB in enhancing starch synthesis by stabilizing HY5 and facilitating PIFs degradation under high R:FR light conditions.Conversely,under low R:FR light,PIFs predominantly inhibit starch synthesis.This study provides insight into the physiological and molecular functions of phyB and its downstream transcription factors HY5 and PIFs in starch synthesis regulation,shedding light on the regulatory mechanism by which plants synchronize dynamic light signals with metabolic cues to module starch synthesis.

关 键 词：Arabidopsis thaliana HY5 light signal PHYB PIFs starch synthesis 

分 类 号：Q943.2[生物学—植物学]