Cloning and expression analysis of NtCAD gene from Nicotiana tabacum

In order to clarify the function and regulation patterns of CAD gene in tobacco, a NtCAD gene was isolated from tobacco cultivar K326(Nicotiana tabacum)by homologous cloning. This gene had an open reading frame(ORF)of 1 176 bp, encoding 391 amino acids, and its predicted molecular weight was 38.99 kDa with an isoelectric point of 5.54. The amino acid sequence of NtCAD had conserved domains of CAD protein. The expression level of NtCAD gene in the flower bud, lateral root and fibrous root was relatively high, but it was relatively low in the stalk node and stalk. A low temperature (4 ℃) treatment significantly induced the expression of NtCAD, while the treatment of abscisic acid(ABA)caused the expression of NtCAD to display a cyclical increase, followed by decrease and increase again, which indicated that NtCAD might be involved in the resistance to abiotic stress.