'Plant Breeding: Sustaining the Future' Abstracts of the XVIth EUCARPIA Congress, Edinburgh, Scotland, 10-14 September 2001 IMPROVEMENT OF ALFALFA DIGESTIBILITY BY GENE INVOLVED IN BIOSYNTHESIS M. VLAHOVA, L. CARLIER, E.V. BOCKSTAELE, W. BOERJAN, A. ATANASSOV AgroBioInstitute, 2232-Kostinbrod, Bulgaria

Digestibility is one of the main characteristics of alfalfa as a forage crop.  This trait negatively correlates with lignin content and composition.  The possibility for modification of lignin biosynthesis by genetic transformation with a popular gene CCoAOMT (Caffeoyl CoA 3-O-methyltransferase) from the phenylpropanoid pathway, was investigated.  Constructs, containing the gene in sense and antisense orientations under the control of double 35S promoter and HPT were used as a selection marker.  The lignin content of the molecular characterised transgenic plants (Southern and Western blot) have been determined by two methods – Klason and Acetylbromide.  The data assessment of the impact of the heterologous CCoAMT gene on alfalfa lignin content showed positive plants exhibited normal phenotype and fertility.  Four of the tested transformants possessed less lignin (20-22%) the control.  The above data was confirmed by histochemical (Weisner) reaction.  The analyses of the lignin composition (Thioacidolysis) as well as small field trials are in progress.