title: Arabidopsis thaliana FAR-RED ELONGATED HYPOCOTYLS3 (FHY3) and FAR-RED-IMPAIRED RESPONSE1 (FAR1) modulate starch synthesis in response to light and sugar.
abstract: In living organisms, daily light/dark cycles profoundly affect cellular processes. In plants, optimal growth and development, and adaptation to daily light-dark cycles, require starch synthesis and turnover. However, the underlying molecular mechanisms coordinating daily starch metabolism remain poorly understood. To explore the roles of Arabidopsis thaliana light signal transduction proteins FAR-RED ELONGATED HYPOCOTYLS3 (FHY3) and FAR-RED-IMPAIRED RESPONSE1 (FAR1) in starch metabolism, the contents of starch and water-soluble polysaccharides, and the structure of starch granules were investigated in fhy3, far1 and fhy3 far1 mutant plants. Disruption of FHY3 or FAR1 reduced starch accumulation and altered starch granule structure in the fhy3-4, far1-2, and fhy3-4 far1-2 mutant plants. Furthermore, molecular and genetic evidence revealed that the gene encoding the starch-debranching enzyme ISOAMYLASE2 (ISA2) is a direct target of FHY3 and FAR1, and functions in light-induced starch synthesis. Our data establish the first molecular link between light signal transduction and starch synthesis, suggesting that the light-signaling proteins FHY3 and FAR1 influence starch synthesis and starch granule formation through transcriptional activation of ISA2.
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China.
authors.forename: Na
authors.initials: N
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China.
authors.forename: Haisen
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Li
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism*; D010834:Phytochrome / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects / Q000528:radiation effects; D013213:Starch / Q000096:biosynthesis* / Q000378:metabolism / Q000648:ultrastructure; D000073893:Sugars / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects / Q000528:radiation effects
chemical_list: D029681:Arabidopsis Proteins; C120919:FAR1 protein, Arabidopsis; C452847:FHY3 protein, Arabidopsis; D009687:Nuclear Proteins; D000073893:Sugars; D010834:Phytochrome; D013213:Starch
keywords: 
  Arabidopsis thaliana
  ; FAR-RED ELONGATED HYPOCOTYLS3 (FHY3); FAR-RED-IMPAIRED RESPONSE1 (FAR1); ISOAMYLASE2 (ISA2); light signal proteins; starch synthesis