title: Calcium dependent sucrose uptake links sugar signaling to anthocyanin biosynthesis in Arabidopsis.
abstract: Sugars enhance light signaling-induced anthocyanin accumulation in Arabidopsis seedlings via differential regulation of several positive and negative transcription factors. Ca(2+) plays a role as a second messenger in sugar signaling in grape and wheat. However, whether anthocyanin pigmentation is modulated by changes in intracellular Ca(2+) level in Arabidopsis is not known. Here, we used a pharmaceutical approach that Ca(2+) antagonists strongly interfered with sucrose uptake and anthocyanin accumulation by downregulating the expression of sucrose transporter 1 (SUC1) and transcriptional regulatory factors, such as PAP1. Time course analysis of the effect of Ca(2+) antagonists showed the early inhibition of sucrose-induced sugar uptake leading to decreased anthocyanin accumulation, indicating that Ca(2+) signals play a role in sugar uptake rather than in anthocyanin biosynthesis. An early increase in cytosolic Ca(2+) level in Arabidopsis roots in response to sucrose feeding was significantly inhibited by Ca(2+) antagonists. Taken together, these results indicate that sucrose-induced sugar uptake in Arabidopsis is modulated by changes in endogenous Ca(2+) levels, which in turn regulate anthocyanin accumulation.
authors.affiliation: Department of Biological Sciences, Chungnam National University, Daejeon 305-764, Republic of Korea.
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Shin
authors.forename: Myoung-Goo
authors.initials: MG
authors.lastname: Choi
authors.forename: Hyun Kyoung
authors.initials: HK
authors.lastname: Lee
authors.forename: Misuk
authors.initials: M
authors.lastname: Cho
authors.forename: Sang-Bong
authors.initials: SB
authors.lastname: Choi
authors.forename: Giltsu
authors.initials: G
authors.lastname: Choi
authors.forename: Youn-Il
authors.initials: YI
authors.lastname: Park
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis*; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D026901:Membrane Transport Proteins / Q000378:metabolism; D000073718:Pancreatitis-Associated Proteins; D010940:Plant Proteins / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D029681:Arabidopsis Proteins; D002118:Calcium; D026901:Membrane Transport Proteins; D000073718:Pancreatitis-Associated Proteins; D010940:Plant Proteins; D013395:Sucrose; D014157:Transcription Factors; C502612:AT1G56650 protein, Arabidopsis; C000612141:REG3A protein, human; C078729:sucrose transport protein, plant