title: A QTL for rice grain width and weight encodes a previously unknown RING-type E3 ubiquitin ligase.
abstract: Grain weight is one of the most important components of grain yield and is controlled by quantitative trait loci (QTLs) derived from natural variations in crops. However, the molecular roles of QTLs in the regulation of grain weight have not been fully elucidated. Here, we report the cloning and characterization of GW2, a new QTL that controls rice grain width and weight. Our data show that GW2 encodes a previously unknown RING-type protein with E3 ubiquitin ligase activity, which is known to function in the degradation by the ubiquitin-proteasome pathway. Loss of GW2 function increased cell numbers, resulting in a larger (wider) spikelet hull, and it accelerated the grain milk filling rate, resulting in enhanced grain width, weight and yield. Our results suggest that GW2 negatively regulates cell division by targeting its substrate(s) to proteasomes for regulated proteolysis. The functional characterization of GW2 provides insight into the mechanism of seed development and is a potential tool for improving grain yield in crops.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences, The Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Xian-Jun
authors.initials: XJ
authors.lastname: Song
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Min
authors.initials: M
authors.lastname: Shi
authors.forename: Mei-Zhen
authors.initials: MZ
authors.lastname: Zhu
authors.forename: Hong-Xuan
authors.initials: HX
authors.lastname: Lin
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018556:Crops, Agricultural / Q000235:genetics* / Q000254:growth & development; D014644:Genetic Variation; D008954:Models, Biological; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D010641:Phenotype; D040641:Quantitative Trait Loci; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000166:cytology* / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D044767:Ubiquitin-Protein Ligases / Q000235:genetics*
chemical_list: D044767:Ubiquitin-Protein Ligases