Cloning of a Calcium-Dependent Protein Kinase Gene NtCDPK12, and Its Induced Expression by High-Salt and Drought in Nicotiana tabacum

Calcium-dependent protein kinases (CDPKs, EC 2.7.1.37) comprise a large family of Ser/Thr kinases in plants and play an important role in plant Ca2+ signal transduction. A full-length CDPK gene, NtCDPK12 (GenBank accession number GQ337420), was isolated from common tobacco (Nicotiana tabacum) leaves by rapid amplification of cDNA ends (RACE). The NtCDPK12 cDNA is 1 816 bp length and contains an open reading frame (ORF) of 1 461 bp encoding 486 amino acids. Sequence alignments indicated that NtCDPK12 contains all conserved regions found in CDPKs and shows a high level of sequence similarity to many other plant CDPKs. The results of real-time quantitative reverse transcription-PCR (qRT-PCR) showed that NtCDPK12 was highly expressed in stems and increased in roots treated with high-salt or subjected to drought stress, which indicates that NtCDPK12 was induced by high-salt and drought stresses.