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Researchers in the US succeeded in generating transgenic plants that produce
enhanced levels of folates, leading them one step closer to delivering
adequate folate levels via biofortified foods, October 2004 by Angelika
Kren.

Folate is a form of a water-soluble B vitamin, produced mainly in leafy
greens such as spinach and turnip greens, dry beans and peas, but also some
vegetables and fruits are rich food sources of folate.

In the developed world, another important source for this vitamin are
breakfast cereals that are fortified with folic acid, the synthetic form of
this vitamin. However, natural folate levels are very low in cereals and in
root and tuber crops, the main components in the diet of people in
developing countries.

Since folate is necessary for the production and maintenance of new cells,
it is especially important during periods of rapid cell division and growth,
such as infancy and pregnancy. Hence, reduced levels of this vitamin can
lead to various pathological symptoms. In fact, it has been stated that
inadequate intake of folate before pregnancy is the most common cause of
birth defects.

In plants, folate biosynthesis occurs via a multi-step pathway. Two
essential precursors are called pterins and PABA respectively. As described
in PNAS, Dr. Karel Schubert and his co-workers from the Tufts University,
Boston, aimed to enhance pterin levels by introducing an enzyme that is the
key player in pterin synthesis (GTPcyclohydrolase) into plants (Arabidopsis
thaliana), which might subsequently lead to higher folate levels.

With this approach, Dr. Schubert?s group indeed managed to produce several
transgenic plants that produced a 1250-fold enhancement of pterin levels on
average. Surprisingly, the corresponding folate level enhancement turned out
to be much lower (3.3 fold enhancement), suggesting that yet undiscovered
factors play important roles in this biochemical pathway.

These results helped to identify potential factors regulating folate
synthesis and suggest new ways to further enhance folate levels in food
crops. This work is not the final solution, but it might be one important
step in the development of biofortified foods with increase folate levels.
Above all, but not only developing countries could take an advantage from
this technology as by this means, adequate folate intake of people could be
ensured, independent of the delivery and distribution of synthetic folic
acid food additives. Until this is achieved, though, eating spinach still
seems to be the easiest way to prevent folate deficiency syndromes.

Angelika Kren is a Science Journalist with Checkbiotech, and is a graduate
student at the University of Basel, Switzerland. Look for more articles from
her in the future.

[www.checkbiotech.org];
subtopic_id=2&doc_id=8859

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