Modest calcium increase in tomatoes expressing a variant of Arabidopsis cation/H+ antiporter

The over-expression of Arabidopsis CAX1 and CAX2 causes transgenic tomato plants to reveal severe Ca 2+ deficiency-like symptoms such as tip-burn and/or blossom end rot, despite there being sufficient Ca 2+ in each plant part. To correct the symptoms and to moderately enhance the calcium level, a worldwide vegetable tomato was genetically engineered using a modified Arabidopsis cation/H + antiporter sCAX2A, a mutant form of Arabidopsis CAX2. Compared with the wild-type, the s CAX2A -expressing tomato plants demonstrated elevated Ca 2+ levels in the fruits with almost no changes in the levels of Mn 2+ , Cu 2+ , and Fe 2+ . Moreover, expression of s CAX2A in tomato plants did not show any significant alterations in their morphological phenotypes. Unlike 35S :: sCAX1 construct, s CAX2A antiporter gene driven by 35S promoter can be a valuable tool for enriching Ca 2+ contents in the tomato fruit without additional accumulation of the undesirable cations.