title: Variations in CYP78A13 coding region influence grain size and yield in rice.
abstract: Grain size is one of the most important determinants of crop yield in cereals. Here, we identified a dominant mutant, big grain2 (bg2-D) from our enhancer-trapping population. Genetic analysis and SiteFinding PCR (polymerase chain reaction) revealed that BG2 encodes a cytochrome P450, OsCYP78A13. Sequence search revealed that CYP78A13 has a paralogue Grain Length 3.2 (GL3.2, LOC_Os03g30420) in rice with distinct expression patterns, analysis of transgenic plants harbouring either CYP78A13 or GL3.2 showed that both can promote grain growth. Sequence polymorphism analysis with 1529 rice varieties showed that the nucleotide diversity at CYP78A13 gene body and the 20 kb flanking region in the indica varieties were markedly higher than those in japonica varieties. Further, comparison of the genomic sequence of CYP78A13 in the japonica cultivar Nipponbare and the indica cultivar 9311 showed that there were three InDels in the promoter region and eight SNPs (single nucleotide polymorphism) in its coding sequence. Detailed examination of the transgenic plants with chimaeric constructs suggested that variation in CYP78A13 coding region is responsible for the variation of grain yield. Taken together, our results suggest that the variations in CYP78A13 in the indica varieties hold potential in rice breeding for application of grain yield improvement.
authors.affiliation: State Key Laboratory of Plant Genomics, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China; University of the Chinese Academy of Sciences, Yuquan Road, Beijing, 100039, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Xu
authors.forename: Jun
authors.initials: J
authors.lastname: Fang
authors.forename: Shujun
authors.initials: S
authors.lastname: Ou
authors.forename: Shaopei
authors.initials: S
authors.lastname: Gao
authors.forename: Fengxia
authors.initials: F
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Du
authors.forename: Yunhua
authors.initials: Y
authors.lastname: Xiao
authors.forename: Hongru
authors.initials: H
authors.lastname: Wang
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Sun
authors.forename: Jinfang
authors.initials: J
authors.lastname: Chu
authors.forename: Guodong
authors.initials: G
authors.lastname: Wang
authors.forename: Chengcai
authors.initials: C
authors.lastname: Chu
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development; D018533:Biomass; D002453:Cell Cycle; D049109:Cell Proliferation; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D002523:Edible Grain / Q000235:genetics / Q000254:growth & development; D009154:Mutation; D016366:Open Reading Frames / Q000235:genetics; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA
chemical_list: D010940:Plant Proteins; D003577:Cytochrome P-450 Enzyme System
keywords: cell-cycle; cytochrome P450; grain yield; sequence polymorphisms