Abstract：The CDPK was amplified by RT-PCR from a cucumber cultivar‘Jinyan No. 4’ leaves
cDNA under low nitrogen stress．The sequences of primers were designed based on the Csa002986 gene
coding region in the cucumber genome database，which is using Primer Premier 5.0．The gene is 1 584
bp and encoding 527 amino acids．The protein encoded by this gene was calculated to be a stable and
hydrophilic protein，no transmembrane structure and no signal peptide，and with the protein kinase
domain，and EF-hand calcium-binding domain, and serine/threonine protein kinase active site, and
N-myristoylation site，and so on．Expression analysis of CDPK in various parts of cucumber under
different nitrogen concentration treatment showed that CDPK gene in shoot apex reached the highest
expression level，followed by leaves and stems under the nitrogen-free conditions．CDPK gene expression levels in the stem were the highest，followed by shoot tips and leaves under low nitrogen
conditions．CDPK gene in shoot apex were the highest expression level，followed by stems and
leaves under normal and high nitrogen conditions．CDPK gene expression patterns analysis in leaves
showed that the gene is up-regulated under nitrogen-free and low nitrogen conditions，as the nitrogen
concentration decreased，CDPK gene expression is increased and is significantly higher than the normal
level．The expression of CDPK gene under high nitrogen condition is lower than the normal le vels．
