title: Two rice authentic histidine phosphotransfer proteins, OsAHP1 and OsAHP2, mediate cytokinin signaling and stress responses in rice.
abstract: Cytokinin plays an important role in plant development and stress tolerance. Studies of Arabidopsis (Arabidopsis thaliana) have demonstrated that cytokinin acts through a two-component system that includes a histidine (His) kinase, a His phosphotransfer protein (HP), and a response regulator. Phylogenetic analyses have revealed the conservation of His kinases but lineage-specific expansion of HPs and response regulators in rice (Oryza sativa). However, whether the functions of rice HPs have diverged remains unknown. In this study, two rice authentic HPs (OsAHP1 and OsAHP2) were knocked down simultaneously via RNA interference (RNAi), and the transgenic OsAHP-RNAi plants exhibited phenotypes expected for a deficiency in cytokinin signaling, including dwarfism with reduced internode lengths, enhanced lateral root growth, early leaf senescence, and reduced tiller numbers and fertility under natural conditions. The OsAHP-RNAi seedlings were also hyposensitive to exogenous cytokinin. Furthermore, OsAHP-RNAi seedlings were hypersensitive to salt treatment but resistant to osmotic stress relative to wild-type plants. These results indicate that OsAHPs function as positive regulators of the cytokinin signaling pathway and play different roles in salt and drought tolerance in rice.
authors.affiliation: Hebei Key Laboratory of Molecular and Cellular Biology , Hebei Normal University, Shijiazhuang 050024, China.
authors.forename: Lijing
authors.initials: L
authors.lastname: Sun
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jinxia
authors.initials: J
authors.lastname: Wu
authors.forename: Liqing
authors.initials: L
authors.lastname: Zhang
authors.forename: Xuewen
authors.initials: X
authors.lastname: Jiao
authors.forename: Shengwei
authors.initials: S
authors.lastname: Zhang
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Zhang
authors.forename: Daye
authors.initials: D
authors.lastname: Sun
authors.forename: Tiegang
authors.initials: T
authors.lastname: Lu
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
mesh_terms: D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D003583:Cytokinins / Q000378:metabolism* / Q000494:pharmacology; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D006639:Histidine; D012275:Oryza / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology*; D009997:Osmotic Pressure / Q000187:drug effects; D010641:Phenotype; D010766:Phosphorylation / Q000187:drug effects; D063245:Plant Development / Q000187:drug effects; D010940:Plant Proteins; D018517:Plant Roots / Q000033:anatomy & histology / Q000187:drug effects; D030821:Plants, Genetically Modified; D034622:RNA Interference / Q000187:drug effects; D036226:Seedlings / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects
chemical_list: D003583:Cytokinins; D010940:Plant Proteins; D012965:Sodium Chloride; D006639:Histidine