title: Leucine-rich repeat receptor-like kinase1 is a key membrane-bound regulator of abscisic acid early signaling in Arabidopsis.
abstract: Abscisic acid (ABA) is important in seed maturation, seed dormancy, stomatal closure, and stress response. Many genes that function in ABA signal transduction pathways have been identified. However, most important signaling molecules involved in the perception of the ABA signal or with ABA receptors have not been identified yet. Receptor-like kinase1 (RPK1), a Leu-rich repeat (LRR) receptor kinase in the plasma membrane, is upregulated by ABA in Arabidopsis thaliana. Here, we show the phenotypes of T-DNA insertion mutants and RPK1-antisense plants. Repression of RPK1 expression in Arabidopsis decreased sensitivity to ABA during germination, growth, and stomatal closure; microarray and RNA gel analysis showed that many ABA-inducible genes are downregulated in these plants. Furthermore, overexpression of the RPK1 LRR domain alone or fused with the Brassinosteroid-insensitive1 kinase domain in plants resulted in phenotypes indicating ABA sensitivity. RPK1 is involved in the main ABA signaling pathway and in early ABA perception in Arabidopsis.
authors.affiliation: Biological Resources Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305-8686, Japan.
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Osakabe
authors.forename: Kyonoshin
authors.initials: K
authors.lastname: Maruyama
authors.forename: Motoaki
authors.initials: M
authors.lastname: Seki
authors.forename: Masakazu
authors.initials: M
authors.lastname: Satou
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
authors.forename: Kazuko
authors.initials: K
authors.lastname: Yamaguchi-Shinozaki
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000196:embryology* / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics; D004351:Drug Resistance / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D009154:Mutation / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000235:genetics; D012639:Seeds / Q000196:embryology* / Q000201:enzymology* / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D000040:Abscisic Acid; D011494:Protein Kinases; C105762:RPK1 protein, Arabidopsis