Vitamin B1 Biosynthesis in Plants

Vitamin B1 is an essential compound in all organisms acting as a cofactor (“helper molecules” required for enzyme activity) of enzymes necessary for numerous metabolic pathways. In plants, vitamin B1, in the form of thiamin diphosphate, has been implicated for tolerance to DNA damage and as an activator of disease resistance. Vitamin B1 deficiency remains a worldwide problem, especially in countries where rice serves as the staple food, since grain polishing removes most of the vitamin that is present in the bran. Plants are major source of vitamin B1 for animals and humans, yet not much is known about the biosynthesis of the compound therein.

A group of researchers from Switzerland and Germany made an important discovery in the biosynthetic pathway of vitamin B1. Using Arabidopsis as a model plant; the scientists discovered that vitamin B1 synthesis in plants is very much similar to that of bacteria. The researchers identified a protein, very much similar to THIC—the key enzyme for vitamin B1 synthesis in bacteria. The THIC homolog was found to be essential for plant viability. The discovery opens possible ways to alter the levels of vitamin B1 in plants through genetic engineering.

The full paper published by PNAS can be accessed at http://www.pnas.org/cgi/reprint/0709597104v1  The abstract is available at http://www.pnas.org/cgi/content/abstract/0709597104v1