ARS | Publication request: EXPRESSION OF AN ARABIDOPSIS CA2+/H+ TRANSPORTER INCREASES BIOAVAILABLE CA2+ IN EDIBLE CARROT ROOTS

Submitted to: Plant Biology
Publication Type: Abstract Only
Publication Acceptance Date: August 9, 2006
Publication Date: August 9, 2006
Citation: Morris, J., Park, S., Kim, J., Nakata, P.A., Hirschi, K. 2006. Expression of an arabidopsis ca2+/h+ transporter increases bioavailable ca2+ in edible carrot roots [abstract]. Plant Biology. p. 161.

Technical Abstract: Our long range goal is to make vegetables a better source of dietary calcium. We demonstrate that carrots expressing the Arabidopsis H+/Ca2+ transporter sCAX1 contain up to 50% more calcium compared to plants transformed with the vector only. These modified carrots were fertile and robust, with no discernable difference compared to vector control. The immediate question becomes whether this increase alters the level of bioavailable calcium. Using a mouse model for estimating calcium bioavailability, our findings suggest that treatment diets containing sCAX1 carrots extrinsically labeled with 45Ca have no difference in the percent absorption into the femurs compared to labeled diets containing control carrots. To examine the usefulness of extrinsic labeling techniques, we intrinsically labeled the carrots with 45Ca. Mice feed both control and sCAX1 carrots, which were intrinsically labeled with 45Ca, did not have any difference in percent absorption into their femurs. The percent absorptions between the extrinsically and intrinsically labeled carrot diets were not different. To determine if these findings have relevance for human nutrition, future work will be done feeding stable isotope labeled sCAX1 carrots to adolescent children. Our findings suggest that a higher concentration of calcium from sCAX1 carrots does not alter calcium absorption in mice. Our initial observations suggest we have created a novel way of fortifying vegetables with bioavailable calcium.