A genomic approach to nutritional, pharmacological and genetic issues of faba bean (Vicia faba): prospects for genetic modifications.

Cultivated faba bean (Vicia faba) is widely used as human food, especially in Europe, Northern Africa and China.  In view of its superior feeding value over field peas or other legumes, it is also widely used as animal feed for a variety of species.   V. faba also contains medically important components such as 3,4-dihydroxyphenylalanine (levo-DOPA, L-DOPA), the principal treatment used for Parkinson's disease patients.  However, this species also contains several antinutritional components, including the pyrimidine glycosides vicine and convicine; phytates; and the sucrose galactosides including raffinose, stachyose and verbascose.  We have undertaken a genomic project to provide publicly available expressed sequence tag sequences (EST) prepared from early to mid developing embryo in an attempt to identify genes that are likely to be involved in the biosynthesis of L-DOPA and the vicine group of compounds.  As initial examples of the utility of this approach, we describe the complete sequence of fabatin, new defensins, type 4 metallothioneins and a variety of other key genes which were identified in this EST library. No candidate sequences corresponding to the biosynthesis of L-DOPA or the vicine group could be identified at this early stage of seed development.