title: Erect panicle2 encodes a novel protein that regulates panicle erectness in indica rice.
abstract: Rice (Oryza sativa L.) inflorescence (panicle) architecture is an important agronomic trait for rice breeding. A number of high-yielding japonica rice strains, characterized by an erect panicle (EP) of their architecture, have been released as commercial varieties in China. But no EP-type indica varieties are released so far. Here, we identified two allelic erect-panicle mutants in indica rice, erect panicle2-1 (ep2-1) and erect panicle2-2 (ep2-2), exhibiting the characteristic erect panicle phenotype. Both mutants were derived from spontaneous mutation. We cloned the EP2 gene by way of a map-based cloning strategy, and a transgenic complementation test rescued the phenotype of ep2-1. Anatomical investigations revealed that the ep2 mutants have more vascular bundles and a thicker stem than that of wild-type plants, explaining the panicle erectness phenotype in ep2 mutants. It was shown that EP2 was specifically expressed in the vascular bundles of internodes by GUS staining and RT-PCR. EP2 encodes a novel plant-specific protein, which localizes to the endoplasmic reticulum with unknown biochemical function. In addition, EP2 also regulates other panicle characteristics, such as panicle length and grain size, but grain number per panicle shows little change, indicating that the mutation of the ep2 gene could be applied in EP-type indica rice breeding.
authors.affiliation: State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Keming
authors.initials: K
authors.lastname: Zhu
authors.forename: Ding
authors.initials: D
authors.lastname: Tang
authors.forename: Changjie
authors.initials: C
authors.lastname: Yan
authors.forename: Zhengchang
authors.initials: Z
authors.lastname: Chi
authors.forename: Hengxiu
authors.initials: H
authors.lastname: Yu
authors.forename: Jianmin
authors.initials: J
authors.lastname: Chen
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Liang
authors.forename: Minghong
authors.initials: M
authors.lastname: Gu
authors.forename: Zhukuan
authors.initials: Z
authors.lastname: Cheng
mesh_terms: D032461:Chromosomes, Plant / Q000235:genetics; D003001:Cloning, Molecular; D004721:Endoplasmic Reticulum / Q000378:metabolism; D035264:Flowers / Q000033:anatomy & histology* / Q000166:cytology / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000033:anatomy & histology* / Q000166:cytology / Q000235:genetics*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D021381:Protein Transport; D013045:Species Specificity
chemical_list: D010940:Plant Proteins