title: Down-regulation of a LBD-like gene, OsIG1, leads to occurrence of unusual double ovules and developmental abnormalities of various floral organs and megagametophyte in rice.
abstract: The indeterminate gametophyte1 (ig1) mutation was first characterized to modulate female gametophyte development in maize (Zea mays). However, the function of its rice orthologue, OsIG1, remains unknown. For this, we first analysed OsIG1 localization from differential tissues in rice. Real-time quantitative PCR (qRT-PCR) and histochemical staining results demonstrated that the expression signal of OsIG1 was strongly detected in young inflorescence, moderately in mature flower and weakly in leaf. Furthermore, RNA in situ hybridization analyses exhibited that OsIG1 was strongly expressed in inflorescence meristems, floral meristems, empty-glume- and floret- primordia, especially in the primordia of stamens and immature ovules, and the micropylar side of the mature ovary. In OsIG1-RNAi lines, wrinkled blade formation was accompanied by increased leaf inclination angle. Cross-section further showed that the number of bulliform cells located between the vasculatures was significantly increased, indicating that OsIG1 is involved in division and differentiation of bulliform cell and lateral growth during leaf development. OsIG1-RNAi suppression lines showed pleiotropic phenotypes, including degenerated palea, glume-like features and open hull. In addition, a single OsIG1-RNAi floret is characterized by frequently developing double ovules with abnormal embryo sac development. Additionally, down-regulation of OsIG1 differentially affected the expression of genes associated with the floral organ development including EG1, OsMADS6 and OsMADS1. Taken together, these results demonstrate that OsIG1 plays an essential role in the regulation of empty-glume identity, floral organ number control and female gametophyte development in rice.
authors.affiliation: Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China.
authors.forename: Jingrong
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Tang
authors.affiliation: National Key Laboratory of Crop Genetics and Improvement, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Yulan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China.
authors.forename: Xiangli
authors.initials: X
authors.lastname: Niu
authors.affiliation: National Key Laboratory of Crop Genetics and Improvement, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China liuyongsheng1122@hfut.edu.cn yi.han@hfut.edu.cn.
authors.forename: Yi
authors.initials: Y
authors.lastname: Han
authors.affiliation: Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China liuyongsheng1122@hfut.edu.cn yi.han@hfut.edu.cn.
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D015536:Down-Regulation; D035264:Flowers / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D055993:Germ Cells, Plant / Q000254:growth & development / Q000378:metabolism; D018519:Meristem / Q000235:genetics; D012275:Oryza / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D010940:Plant Proteins
keywords: OsIG1; embryo sac; empty glume; female gametophyte; ovule.