Plant & Animal Genomes XIII Conference Plant & Animal Genomes XIII ConferenceJanuary 15-19, 2005
Town & Country Convention Center
San Diego, CA
Iryna Vasylenko , Fares Najar , Bruce A. Roe
Medicago truncatula flavonoid genes are fairly evenly distributed throughout 7 of its 8 chromosomes but underrepresented on chromosome 6. Many of the flavonoid genes are clustered, while others occur individually. For example, chalcone synthase, flavonoid 3’, 5’-hydroxylase, flavonol 3-O-glucosyltransferase are combined into single 5-7 gene clusters. Chalcone synthase, a branchpoint enzyme in the early flavonoid biosynthesis is represented by two such clusters on the chromosomes V and VII and also occurs as single genes on chromosomes V, VII, VIII. In contrast, phenylalanine ammonium lyase, also an early enzyme in the flavonoid synthesis, is represented by a few single genes only on chromosome I.
Flavonoid 3’-hydroxylase, dihydroflavonol-4-reductase, leucoanthocyanidin dioxygenase, flavonoid 7-O-methyltransferase occur as 2-4 gene single clusters or located as multiple single genes on all chromosomes, but the genes for flavonoid 7-O-methyltransferase are found only on chromosomes V and VII. All other predicted flavonoid genes exist as multiple single genes.
The genome organization of M. truncatula chalcone synthase cluster on chromosome VII is similar to that of A. thaliana chalcone synthase since it is flanked on the left side with functional formyltetrahydrofolate deformylase and on the right side with identical hypothetical protein. The flavonoid 3-hydroxylase cluster on chromosome VIII corresponds to the A.thaliana cytochrome P450 cluster and surrounded with similar functional proteins. Flavonoid 3’-hydroxylase and dihydroflavonol-4-reductase clusters also are surrounded with similar hypothetical or unknown proteins. It therefore is likely that the genome organization of most flavonoid genes in M. truncatula is similar to that of A. thaliana