title: Isolation and initial characterization of GW5, a major QTL associated with rice grain width and weight.
abstract: Grain weight is a major determinant of crop grain yield and is controlled by naturally occurring quantitative trait loci (QTLs). We earlier identified a major QTL that controls rice grain width and weight, GW5, which was mapped to a recombination hotspot on rice chromosome 5. To gain a better understanding of how GW5 controls rice grain width, we conducted fine mapping of this locus and uncovered a 1 212-bp deletion associated with the increased grain width in the rice cultivar Asominori, in comparison with the slender grain rice IR24. In addition, genotyping analyses of 46 rice cultivars revealed that this deletion is highly correlated with the grain-width phenotype, suggesting that the GW5 deletion might have been selected during rice domestication. GW5 encodes a novel nuclear protein of 144 amino acids that is localized to the nucleus. Furthermore, we show that GW5 physically interacts with polyubiquitin in a yeast two-hybrid assay. Together, our results suggest that GW5 represents a major QTL underlying rice width and weight, and that it likely acts in the ubiquitin-proteasome pathway to regulate cell division during seed development. This study provides novel insights into the molecular mechanisms controlling rice grain development and suggests that GW5 could serve as a potential tool for high-yield breeding of crops.Cell Research (2008) 18:1199-1209. doi: 10.1038/cr.2008.307; published online 18 November 2008.
authors.affiliation: National Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Weng
authors.forename: Suhai
authors.initials: S
authors.lastname: Gu
authors.forename: Xiangyuan
authors.initials: X
authors.lastname: Wan
authors.forename: He
authors.initials: H
authors.lastname: Gao
authors.forename: Tao
authors.initials: T
authors.lastname: Guo
authors.forename: Ning
authors.initials: N
authors.lastname: Su
authors.forename: Cailin
authors.initials: C
authors.lastname: Lei
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Cheng
authors.forename: Xiuping
authors.initials: X
authors.lastname: Guo
authors.forename: Jiulin
authors.initials: J
authors.lastname: Wang
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang
authors.forename: Huqu
authors.initials: H
authors.lastname: Zhai
authors.forename: Jianmin
authors.initials: J
authors.lastname: Wan
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000378:metabolism; D017353:Gene Deletion; D017343:Genes, Plant; D012275:Oryza / Q000235:genetics* / Q000254:growth & development*; D025821:Polyubiquitin / Q000378:metabolism; D040641:Quantitative Trait Loci
chemical_list: D025821:Polyubiquitin