title: Beak-shaped grain 1/TRIANGULAR HULL 1, a DUF640 gene, is associated with grain shape, size and weight in rice.
abstract: Grain shape and size both determine grain weight and therefore crop yield. However, the molecular mechanisms controlling grain shape and size are still largely unknown. Here, we isolated a rice mutant, beak-shaped grain1 (bsg1), which produced beak-shaped grains of decreased width, thickness and weight with a loosely interlocked lemma and palea that were unable to close tightly. Starch granules were also irregularly packaged in the bsg1 grains. Consistent with the lemma and palea shapes, the outer parenchyma cell layers of these bsg1 tissues developed fewer cells with decreased size. Map-based cloning revealed that BSG1 encoded a DUF640 domain protein, TRIANGULAR HULL 1, of unknown function. Quantitative PCR and GUS fusion reporter assays showed that BSG1 was expressed mainly in the young panicle and elongating stem. The BSG1 mutation affected the expression of genes potentially involved in the cell cycle and GW2, an important regulator of grain size in rice. Our results suggest that BSG1 determines grain shape and size probably by modifying cell division and expansion in the grain hull.
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, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Yan
authors.forename: Ya
authors.initials: Y
authors.lastname: Zhou
authors.forename: Shenghai
authors.initials: S
authors.lastname: Ye
authors.forename: Longjun
authors.initials: L
authors.lastname: Zeng
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Zhang
authors.forename: Zuhua
authors.initials: Z
authors.lastname: He
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D003001:Cloning, Molecular; D002523:Edible Grain / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D040641:Quantitative Trait Loci / Q000235:genetics*
chemical_list: D018797:Cell Cycle Proteins; D010940:Plant Proteins; D005966:Glucuronidase