VfCPK1, a gene encoding calcium-dependent protein kinase from Vicia faba, is induced by drought and abscisic acid.

Calcium, one of the most ubiquitous second messengers, has been shown to be involved in a wide variety of responses in plants. Calcium-dependent protein kinases (CDPKs) (EC 2.7.1.37) are the predominant Ca(2+)-regulated serine/threonine protein kinase in plants and play an important role in plant calcium signal transduction. CDPKs are encoded by a large multigene family in many plants, which has been showed so far; however, the precise role of each specific CDPK is still largely unknown. A novel CDPK gene designated as VfCPK1 was cloned from epidermal peels of broad bean (Vicia faba L.) leaves using the rapid amplification of cDNA ends (RACE)-PCR technique and its expression was studied in detail. The VfCPK1 cDNA is 1783 bp long and contains an open reading frame of 1482 bp encoding 493 amino acids. VfCPK1 contains all conserved regions found in CDPKs and shows a high level of sequence similarity to many other plant CDPKs. VfCPK1 was highly expressed in leaves, especially in leaf epidermal peels of broad bean in mRNA and protein levels. Expressions of VfCPK1 at both the mRNA and protein levels were increased in leaves treated with abscisic acid or subjected to drought stress. Potential roles of VfCPK1 in epidermal peels are discussed. The nucleotide sequence data reported here were deposited in the GenBank database under accession number AY753552.