Isolation and expression pattern analysis of two ferritin genes in tobacco

For understanding of the ferritin gene expression pattern and the mechanism of iron homeostasis in tobacco (Nicotiana tabaccum L.) plants, two full-length ferritin cDNAs, NtFer1 and NtFer2, were isolated from tobacco seedlings and characterized. These cDNAs are 1214 and 1 125 bp nucleotides and encode 251 and 259 amino acid residues, respectively. The deduced amino acid sequences showed that two tobacco ferritins share the same characteristics as the plant ferritins from Arabidopsis, soybean, and maize. Southern blotting analysis indicated that both NtFer1 and NtFer2 were probably multicopy genes in the tobacco genome. Northern blotting analysis indicated that iron loading of tobacco plantlets increased the ferritin mRNA abundance and that NtFer1 expression was higher and more sensitive to iron than NtFer2 expression. Furthermore, NtFer1 was expressed in both leaves and roots, whereas NtFer2 was expressed mainly in leaves.