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Molecular cloning, characterization, tissue-specific and phytohormone-induced expression of calcium-dependent protein kinase gene in cucumber (Cucumis sativus L.)

Kumar, Suresh KG and Ullanat, Rajesh and Jayabaskaran, Chelliah (2004) Molecular cloning, characterization, tissue-specific and phytohormone-induced expression of calcium-dependent protein kinase gene in cucumber (Cucumis sativus L.). In: Journal of Plant Physiology, 161 (9). pp. 1061-1071.

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Abstract

A cucumber cDNA designated CsCPK5 and encoding a calcium-dependent protein kinase (CsCDPK5) was isolated and characterized. An open reading frame of 1542 bp was detected that could encode a protein of 514 amino acid residues with a calculated molecular mass of 56.5 kDa. Comparison of the deduced amino acid sequence of CsCDPK5 with sequences of other CDPKs revealed the highest similarity (85%) to AtCDPK6. As described for other CDPKs, CsCDPK5 has a long variable domain preceding a catalytic domain, an autoinhibitory function domain, and a C-terminal calmodulindomain containing 4 EF-hand calcium-binding motifs. The N-terminal long variable domain of CsCDPK5 does not contain the N-myristoylation motif, which is found in many CDPKs. The relative expression level of the CsCPK genes in various organs of cucumber plants and seedlings and in etiolated, excised cotyledons and hypocotyls following treatments with light and/or benzyladenine (BA), abscisic acid (ABA), gibberellic acid (GA) or indole acetic acid (IAA) was determined by northern analysis using the CsCPK5 cDNA probe. The CsCPK transcripts are most abundant in cucumber plant leaves with less accumulation in cucumber seedling roots and hypocotyls and lowest levels in cucumber plant flowers and seedling hooks and cotyledons. All phytohormones tested enhanced the accumulation of the transcripts 2–3-fold in etiolated cotyledons. On the other hand, levels of the transcripts increased to a lesser extent in both light and BA- or IAA-treated cotyledons and no effect was noted in response to light treatment with GA. In hypocotyls, no major changes in the relative levels of CsCPK transcripts were observed in the phytohormone-treated etiolated and light-exposed tissues, except an up-regulatory effect with IAA treatment in the etiolated and IAA, ABA and GA treatments in light-exposed hypocotyls. These observations suggest that exogenous phytohormones can up-regulate the CsCPK transcript levels in tissue-specific, and light-dependent and independent manners.

Item Type: Journal Article
Additional Information: The copyright of this article belongs to Elsevier.
Keywords: Calcium-dependent protein kinase;CsCPK5;Cucumis sativus L.;Gene structure;Phytohormones;Tissue-specific gene expression
Department/Centre: Division of Biological Sciences > Biochemistry
Date Deposited: 22 Mar 2006
Last Modified: 19 Sep 2010 04:25
URI: http://eprints.iisc.ernet.in/id/eprint/6122

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