Vitamins are essential nutrients in the human diet, most often acquired from plant-based foods. In
plants, these compounds play a pivotal role in growth and development.
Thiamin (vitamin B1) is required in key steps of central metabolism. Deficiency in humans leads to
severe cardiovascular and neural pathologies. The vitamin B1 pool consists of a mixture of thiaminrelated
molecules (thiamin vitamers) harboring no (thiamin), one (TMP, thiamin monophosphate),
or two (TPP, thiamin pyrophosphate) phosphate groups. Several biological roles have been
attributed to TPP. To make TPP and let it act on its cellular targets, plants have to transport TPP
precursors (B1 vitamers) across the membranes of different entities within the cell, the organelles.
This transport is predicted to occur by the action of transporter proteins, most of which remain to
be identified. Furthermore, thiamin is assumed to be transported over long distance from leaves to
other organs within the plant body.
In this project we propose to identify vitamin B1 transporters by screening for the ability of these
proteins to rescue mutant yeast which needs a vitamin B1 transporter to survive, as well as by
screening mutant Arabidopsis plants, resistant to harmful thiamin analogs. Furthermore, we
propose to utilize this acquired knowledge on vitamin B1 transporters of Arabidopsis to improve our
understanding on the accumulation of vitamin B1 in rice kernels, staple food for half of the world
population.