The salt stress-inducible protein kinase gene, Esi47, from the salt-tolerant wheatgrass Lophopyrum elongatum is involved in plant hormone signaling.
Protein kinases play a central role in signal transduction in all organisms and to study signal transduction in response to salt stress we have identified and characterized a gene encoding a protein kinase that is induced by salt stress and abscisic acid (ABA) in the salt-tolerant wild wheatgrass Lophopyrum elongatum (Host) A. Love. The product of the early salt stress-induced gene, Esi47, was found to belong to the "novel Arabidopsis protein kinase" group of plant serine/threonine protein kinases. Transient gene expression assays in barley aleurone tissue showed Esi47 to suppress the gibberellin induction of the barley low-pI alpha-amylase gene promoter, thus providing evidence for the role of this protein kinase gene in plant hormone signaling. Esi47 contains a small upstream open reading frame in the 5'-untranslated region of its transcript that is implicated in mediating the repression of the basal level of the gene expression and in regulating the ABA inducibility of the gene, as shown in the transient gene expression assay in maize callus. Three Arabidopsis homologs of Esi47 were identified, and different members of this clade of genes showed differential patterns of regulation by salt stress and ABA in Arabidopsis roots and leaves. At least one of the Arabidopsis homologs contains a small open reading frame in its 5'-untranslated region, indicating that the unusual regulatory mechanism identified in Esi47 may be widely conserved.
Centre for Structural and Functional Genomics and Department of Biology, Concordia University, 1455 de Maisonneuve Boulevard West, Montreal, Quebec, Canada H3G 1M8.
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Shen
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Gómez-Cadenas
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Routly
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Ho
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Simmonds
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Gulick
D020121:5' Untranslated Regions; D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D001483:Base Sequence; D018744:DNA, Plant; D001467:Hordeum / Q000502:physiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins; D006109:Poaceae / Q000201:enzymology / Q000235:genetics*; D011494:Protein Kinases / Q000235:genetics*; D015398:Signal Transduction; D012965:Sodium Chloride
D020121:5' Untranslated Regions; D018744:DNA, Plant; D010937:Plant Growth Regulators; D010940:Plant Proteins; D012965:Sodium Chloride; D011494:Protein Kinases; C431891:Esi47 protein, Lophopyrum elongatum