title: Differential expression of GS5 regulates grain size in rice.
abstract: Grain weight is a major determinant of grain yield. GS5 is a positive regulator of grain size such that grain width, filling, and weight are correlated with its expression level. Previous work suggested that polymorphisms of GS5 in the promoter region might be responsible for the variation in grain size. In this study, two single nucleotide polymorphisms (SNPs) between the wide-grain allele GS5-1 and the narrow-grain allele GS5-2 in the upstream region of the gene that were responsible for the differential expression in developing young panicles were identified. These two polymorphs altered the responses of the GS5 alleles to abscisic acid (ABA) treatments, resulting in higher expression of GS5-1 than of GS5-2 in developing young panicles. It was also shown that SNPs in light-responsive elements of the promoter altered the response to light induction, leading to higher expression of GS5-2 than GS5-1 in leaves. Enhanced expression of GS5 competitively inhibits the interaction between OsBAK1-7 and OsMSBP1 by occupying the extracellular leucine-rich repeat (LRR) domain of OsBAK1-7, thus preventing OsBAK1-7 from endocytosis caused by interacting with OsMSBP1, providing an explanation for the positive association between grain size and GS5 expression. These results advanced our understanding of the molecular mechanism by which GS5 controls grain size.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Chunjue
authors.initials: C
authors.lastname: Xu
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Yibo
authors.initials: Y
authors.lastname: Li
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xu
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Caiguo
authors.initials: C
authors.lastname: Xu
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Xianghua
authors.initials: X
authors.lastname: Li
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Jinghua
authors.initials: J
authors.lastname: Xiao
authors.affiliation: National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China qifazh@mail.hzau.edu.cn.
authors.forename: Qifa
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D004705:Endocytosis / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000032:analysis; D012275:Oryza / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000032:analysis / Q000235:genetics* / Q000502:physiology; D020641:Polymorphism, Single Nucleotide / Q000502:physiology; D040641:Quantitative Trait Loci; D014026:Nicotiana / Q000235:genetics
chemical_list: D010937:Plant Growth Regulators; D010940:Plant Proteins; D049452:Green Fluorescent Proteins
keywords: GS5.; cis-element; competitive interaction; differential regulation; expression variation; grain size