| dc.description.abstract | Functional foods go beyond simply supplying nutrients and are increasingly
becoming a focus in the prevention and treatment of disease; however, the benefits of
biofortified crops to human nutrition have not been well demonstrated. Modern
breeding, molecular genetics, and biotechnology are currently focusing on how to
improve the nutritional content in foods. Potatoes, carrots, and lettuce are popular
vegetables eaten today and are targets in developing nutrient dense crops
(biofortification). Biofortification of vegetables to increase calcium (Ca) in the diet has
had promising results. Here we describe the current standing of nutrient biofortification
of crops.
Ca distribution within the plant cell moderates critical functions from signaling to
growth and development and can affect overall plant vigor. The endoplasmic reticulum
(ER) located Ca-ATPase ACA2 (Arabidopsis Ca-ATPase, isoform 2) is thought to play a
role in intracellular calcium homeostasis. In yeast studies; a truncated pump (Δ80-
ACA2) lacking the N-terminal region is about 10-fold more active than the full-length
ACA2 pump. Single point mutations have been shown to increase activity of ACA2 in yeast as well. Previously in our lab, human feeding studies demonstrated that increased
Ca accumulation and bioavailability in transgenic plants accompanied increased activity
of the deregulated vacuolar Ca / H antiporter CAX1 (Cation Exchanger 1) termed
sCAX1.
In this study, transgenic tobacco plants expressing deregulated Ca transporters
are compared. The phenotypes of deregulated vacuolar localized CAX and the ER
localized ACA2 are compared. These results suggest deregulation of ACA2 may
provide an additional tool to utilize in altering the calcium accumulation in agriculturally
important crops. | en |
