Method for modifying lignin composition and increasing in vivo digestibility of forages

摘要

Methods for transforming forage legumes or woody plants with a DNA construct comprising at least one open reading frame encoding for a caffeoyl CoA 3-O-methyltransferase enzyme or a Medicago sativa caffeic acid 3-O-methyltransferase enzyme or a fragment thereof in either a sense or antisense orientation under a lignification-associated tissue specific promoter have been found, resulting in the down-regulation of the corresponding homologous gene either through antisense inhibition or sense suppression, as well as reduced lignin content and modified lignin composition in the transgenic plants. The expression of the caffeoyl CoA 3-O-methyltransferase transgene produces an increased syringyl lignin to guaiacyl lignin ratio in the transformed plant, and greatly improved forage digestibility.