Fuente: WIPO "biotechnology" The present invention relates to methods and genetic constructs for the control of expression of enzymes involved in lignin biosynthesis in plants. The method involves the use of double-stranded RNAi to down-regulate or knock out the expression of the CAD and COMT genes. In particular embodiments the method involves the use of cob-specific or cob-preferred promoters for down-regulation of lignin biosynthesis in the cobs of corn plants.