Tomato Bioengineered to Increase Folate

Deficiency in folate, also known as Vitamin B9, may cause various diseases in humans such birth defects, anemia, cardiovascular diseases, and some cancers. Because of the importance of folate especially to pregnant women, food fortification programs are being implemented in many countries.

Researchers at the University of Florida explored a way to increase the amount of the micronutrient in tomato using metabolic engineering. The group of Rocio Diaz de la Garza produced a double transgenic tomato that produces folate levels equivalent to the adult recommended dietary allowance in a single standard serving. The tomato derived from crossing two lines that are overexpressing folate precursor compounds called ‘GTP cyclohydrolase I’ and ‘aminodeoxychorismate synthase’.

Diaz de la Garza and colleagues have determined that the folate levels in the transgenic fruit increased continuously throughout ripening. The researchers also reported that folate levels in ethylene-treated fruits were very similar to those that were vine-ripened. The research demonstrated a double-gene approach for folate biofortification is feasible and the group recommends that the strategy be adopted to enhance folate production in other plant species.

The complete article can be accessed at http://www.pnas.org/cgi/doi/10.1073/pnas.0700409104. An editorial pointing to the significance of the research is also available at http://www.pnas.org/cgi/doi/10.1073/pnas.0700640104.