title: CBL1, a calcium sensor that differentially regulates salt, drought, and cold responses in Arabidopsis.
abstract: Although calcium is a critical component in the signal transduction pathways that lead to stress gene expression in higher plants, little is known about the molecular mechanism underlying calcium function. It is believed that cellular calcium changes are perceived by sensor molecules, including calcium binding proteins. The calcineurin B-like (CBL) protein family represents a unique group of calcium sensors in plants. A member of the family, CBL1, is highly inducible by multiple stress signals, implicating CBL1 in stress response pathways. When the CBL1 protein level was increased in transgenic Arabidopsis plants, it altered the stress response pathways in these plants. Although drought-induced gene expression was enhanced, gene induction by cold was inhibited. In addition, CBL1-overexpressing plants showed enhanced tolerance to salt and drought but reduced tolerance to freezing. By contrast, cbl1 null mutant plants showed enhanced cold induction and reduced drought induction of stress genes. The mutant plants displayed less tolerance to salt and drought but enhanced tolerance to freezing. These studies suggest that CBL1 functions as a positive regulator of salt and drought responses and a negative regulator of cold response in plants.
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: Yong Hwa
authors.initials: YH
authors.lastname: Cheong
authors.forename: Kyung-Nam
authors.initials: KN
authors.lastname: Kim
authors.forename: Girdhar K
authors.initials: GK
authors.lastname: Pandey
authors.forename: Rajeev
authors.initials: R
authors.lastname: Gupta
authors.forename: John J
authors.initials: JJ
authors.lastname: Grant
authors.forename: Sheng
authors.initials: S
authors.lastname: Luan
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D020013:Calcium Signaling / Q000502:physiology*; D003080:Cold Temperature; D018744:DNA, Plant / Q000235:genetics; D015870:Gene Expression; D017343:Genes, Plant; D005819:Genetic Markers; D009154:Mutation; D009997:Osmotic Pressure; D030821:Plants, Genetically Modified; D012965:Sodium Chloride / Q000494:pharmacology; D014867:Water / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D005819:Genetic Markers; D014867:Water; D012965:Sodium Chloride