title: OsbZIP58, a basic leucine zipper transcription factor, regulates starch biosynthesis in rice endosperm.
abstract: Starch composition and the amount in endosperm, both of which contribute dramatically to seed yield, cooking quality, and taste in cereals, are determined by a series of complex biochemical reactions. However, the mechanism regulating starch biosynthesis in cereal seeds is not well understood. This study showed that OsbZIP58, a bZIP transcription factor, is a key transcriptional regulator controlling starch synthesis in rice endosperm. OsbZIP58 was expressed mainly in endosperm during active starch synthesis. osbzip58 null mutants displayed abnormal seed morphology with altered starch accumulation in the white belly region and decreased amounts of total starch and amylose. Moreover, osbzip58 had a higher proportion of short chains and a lower proportion of intermediate chains of amylopectin. Furthermore, OsbZIP58 was shown to bind directly to the promoters of six starch-synthesizing genes, OsAGPL3, Wx, OsSSIIa, SBE1, OsBEIIb, and ISA2, and to regulate their expression. These findings indicate that OsbZIP58 functions as a key regulator of starch synthesis in rice seeds and provide new insights into seed quality control.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, PR China.
authors.forename: Jie-Chen
authors.initials: JC
authors.lastname: Wang
authors.forename: Heng
authors.initials: H
authors.lastname: Xu
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhu
authors.forename: Qiao-Quan
authors.initials: QQ
authors.lastname: Liu
authors.forename: Xiu-Ling
authors.initials: XL
authors.lastname: Cai
mesh_terms: D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D056625:Endosperm / Q000235:genetics / Q000378:metabolism*; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D013213:Starch / Q000096:biosynthesis*
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D010940:Plant Proteins; D013213:Starch
keywords: Endosperm; OsbZIP58; coordination; rice; starch biosynthesis.