title: OsRACK1 is involved in abscisic acid- and H2O2-mediated signaling to regulate seed germination in rice (Oryza sativa, L.).
abstract: The receptor for activated C kinase 1 (RACK1) is one member of the most important WD repeat-containing family of proteins found in all eukaryotes and is involved in multiple signaling pathways. However, compared with the progress in the area of mammalian RACK1, our understanding of the functions and molecular mechanisms of RACK1 in the regulation of plant growth and development is still in its infancy. In the present study, we investigated the roles of rice RACK1A gene (OsRACK1A) in controlling seed germination and its molecular mechanisms by generating a series of transgenic rice lines, of which OsRACK1A was either over-expressed or under-expressed. Our results showed that OsRACK1A positively regulated seed germination and negatively regulated the responses of seed germination to both exogenous ABA and H2O2. Inhibition of ABA biosynthesis had no enhancing effect on germination, whereas inhibition of ABA catabolism significantly suppressed germination. ABA inhibition on seed germination was almost fully recovered by exogenous H2O2 treatment. Quantitative analyses showed that endogenous ABA levels were significantly higher and H2O2 levels significantly lower in OsRACK1A-down regulated transgenic lines as compared with those in wildtype or OsRACK1A-up regulated lines. Quantitative real-time PCR analyses showed that the transcript levels of OsRbohs and amylase genes, RAmy1A and RAmy3D, were significantly lower in OsRACK1A-down regulated transgenic lines. It is concluded that OsRACK1A positively regulates seed germination by controlling endogenous levels of ABA and H2O2 and their interaction.
authors.affiliation: Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Jiangsu, China.
authors.forename: Dongping
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Jiangsu, China.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Biological Engineering, Huanghuai University, Zhumadian City, Henan Province, China.
authors.forename: Dahong
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Jiangsu, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Lv
authors.affiliation: Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Jiangsu, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America.
authors.forename: Jingui
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Jiangsu, China.
authors.lastname: XuejiaoYan
authors.affiliation: Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Jiangsu, China.
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Liang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D015153:Blotting, Western; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D012275:Oryza / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development*; D016877:Oxidants / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000737:chemistry; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D016877:Oxidants; D010937:Plant Growth Regulators; D012333:RNA, Messenger; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface; D000040:Abscisic Acid; D006861:Hydrogen Peroxide