title: Plant signaling networks involving Ca(2+) and Rboh/Nox-mediated ROS production under salinity stress.
abstract: Salinity stress, which induces both ionic and osmotic damage, impairs plant growth and causes severe reductions in crop yield. Plants are equipped with defense responses against salinity stress such as regulation of ion transport including Na(+) and K(+), accumulation of compatible solutes and stress-related gene expression. The initial Ca(2+) influx mediated by plasma membrane ion channels has been suggested to be crucial for the adaptive signaling. NADPH oxidase (Nox)-mediated production of reactive oxygen species (ROS) has also been suggested to play crucial roles in regulating adaptation to salinity stress in several plant species including halophytes. Respiratory burst oxidase homolog (Rboh) proteins show the ROS-producing Nox activity, which are synergistically activated by the binding of Ca(2+) to EF-hand motifs as well as Ca(2+)-dependent phosphorylation. We herein review molecular identity, structural features and roles of the Ca(2+)-permeable channels involved in early salinity and osmotic signaling, and comparatively discuss the interrelationships among spatiotemporal dynamic changes in cytosolic concentrations of free Ca(2+), Rboh-mediated ROS production, and downstream signaling events during salinity adaptation in planta.
authors.affiliation: School of Bioscience and Biotechnology, Tokyo University of Technology Hachioji, Japan ; Department of Applied Biological Science, Tokyo University of Science Noda, Japan ; Research Institute for Science and Technology, Tokyo University of Science Noda, Japan.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Kurusu
authors.affiliation: Department of Applied Biological Science, Tokyo University of Science Noda, Japan ; Research Institute for Science and Technology, Tokyo University of Science Noda, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Kuchitsu
authors.affiliation: School of Bioscience and Biotechnology, Tokyo University of Technology Hachioji, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Tada
keywords: Ca2+-permeable channels; NADPH oxidases (Noxs); osmotic stress; reactive oxygen species (ROS); salinity stress