Rice WNK1 is regulated by abiotic stress and involved in internal circadian rhythm

In Mammalian system the WNK (with no lysine kinase) serine-threonine protein kinase gene family is suggested to be involved in regulating ion homeostasis and other pathophysiological processes including cancer, hypertension and renal ion transport. In plant system the information about WNK genes is very poor. However, WNK-like genes have also been identified in plants, including ten in Arabidopsis, designated AtWNK1-AtWNK10. Here we report the cloning and characterization of a homologue of AtWNK1 gene from Oryza sativa indica cultivar Pusa Basmati-1 rice and designated as OsWNK1. The specific feature of this gene is lysine residue in kinase subdomain II, which is essential for the coordination of ATP in the active center and conserved among all other kinases, is absent. OsWNK1 was found to respond differentially under various abiotic stresses like cold, heat, salt, drought. OsWNK1 gene showed rhythmic expression profile under diurnal and circadian conditions at the transcription level. Our data indicates that OsWNK1 in rice might play a role in abiotic stress tolerance and that it is involved in internal rhythm.

[1]  D. E. Somers,et al.  The short-period mutant, toc1-1, alters circadian clock regulation of multiple outputs throughout development in Arabidopsis thaliana. , 1998, Development.

[2]  T. Mizuno,et al.  The evolutionarily conserved OsPRR quintet: rice pseudo-response regulators implicated in circadian rhythm. , 2003, Plant & cell physiology.

[3]  D. Alessi,et al.  Activation of the thiazide-sensitive Na+-Cl– cotransporter by the WNK-regulated kinases SPAK and OSR1 , 2008, Journal of Cell Science.

[4]  Kundan Kumar,et al.  Differential regulation of rice mitogen activated protein kinase kinase (MKK) by abiotic stress. , 2008, Plant physiology and biochemistry : PPB.

[5]  Gerhard Grüber,et al.  A WNK kinase binds and phosphorylates V‐ATPase subunit C , 2006, FEBS letters.

[6]  Kundan Kumar,et al.  Rhythmic expression of mitogen activated protein kinase activity in rice , 2009, Molecules and cells.

[7]  Y. Wang,et al.  The plant WNK gene family and regulation of flowering time in Arabidopsis. , 2008, Plant biology.

[8]  J. Dunlap.  Molecular Bases for Circadian Clocks , 1999, Cell.

[9]  Byung-Hoon Lee,et al.  Regulation of WNK1 by an Autoinhibitory Domain and Autophosphorylation* , 2002, The Journal of Biological Chemistry.

[10]  Takeshi Mizuno,et al.  The APRR3 component of the clock-associated APRR1/TOC1 quintet is phosphorylated by a novel protein kinase belonging to the WNK family, the gene for which is also transcribed rhythmically in Arabidopsis thaliana. , 2002, Plant & cell physiology.

[11]  Takeshi Mizuno,et al.  Compilation and Characterization of a Novel WNK Family of Protein Kinases in Arabiodpsis thaliana with Reference to Circadian Rhythms , 2002, Bioscience, biotechnology, and biochemistry.

[12]  Robert J. Schaffer,et al.  Microarray Analysis of Diurnal and Circadian-Regulated Genes in Arabidopsis , 2001, The Plant Cell.

[13]  I. Carré.  Day-length perception and the photoperiodic regulation of flowering in Arabidopsis. , 2001, Journal of biological rhythms.

[14]  Robert J. Unwin,et al.  Human Hypertension Caused by Mutations in WNK Kinases , 2001, Science.

[15]  Marta Matvienko,et al.  Arabidopsis MPSS. An Online Resource for Quantitative Expression Analysis1[w] , 2004, Plant Physiology.

[16]  S. Kay,et al.  Orchestrated transcription of key pathways in Arabidopsis by the circadian clock. , 2000, Science.

[17]  E. Tobin,et al.  All in good time: the Arabidopsis circadian clock. , 2000, Trends in plant science.

[18]  Kundan Kumar,et al.  In Silico Analysis Reveals 75 Members of Mitogen-Activated Protein Kinase Kinase Kinase Gene Family in Rice , 2010, DNA research : an international journal for rapid publication of reports on genes and genomes.

[19]  Peter Jordan,et al.  WNK kinases, a novel protein kinase subfamily in multi-cellular organisms , 2001, Oncogene.

[20]  E. Goldsmith,et al.  WNK1, a Novel Mammalian Serine/Threonine Protein Kinase Lacking the Catalytic Lysine in Subdomain II* , 2000, The Journal of Biological Chemistry.

[21]  D. Alessi,et al.  The regulation of salt transport and blood pressure by the WNK-SPAK/OSR1 signalling pathway , 2008, Journal of Cell Science.

[22]  T. Mizuno,et al.  Comparative overviews of clock-associated genes of Arabidopsis thaliana and Oryza sativa. , 2007, Plant & cell physiology.

[23]  Isabelle A. Carr.  Day-Length Perception and the Photoperiodic Regulation of Flowering in Arabidopsis , 2001 .