Caffeic acid O-methyltransferase (COMT) is a methylation enzyme involved in the early stages of lignin biosynthesis. To examine the effect of antisense expression of a heterologous COMT gene on lignification, an antisense construct of a cDNA encoding a caffeic acid O-methyltransferase ( pOMT8) from Stylosanthes humilis Humb., Bonpl. & Kunth Fabaceae was transferred into tobacco via Agrobacterium tumefaciens. A large number of kanamycin-resistant shoots were recovered after transformation, and randomly selected putative transgenics were analysed for stable integration of the transgene into their genomes. The analyses demonstrated that antisense expression of pOMT8 resulted in reductions in total COMT activity, which was correlated with reduction in the lignin content of the transgenic plants. The amount of lignin in one of the transgenic lines decreased by 62% compared with untransformed control plants.

Caffeic acid O-methyltransferase (COMT) is a methylation enzyme involved in the early stages of lignin biosynthesis. To examine the effect of antisense expression of a heterologous COMT gene on lignification, an antisense construct of a cDNA encoding a caffeic acid O-methyltransferase ( pOMT8) from Stylosanthes humilis Humb., Bonpl. & Kunth Fabaceae was transferred into tobacco via Agrobacterium tumefaciens. A large number of kanamycin-resistant shoots were recovered after transformation, and randomly selected putative transgenics were analysed for stable integration of the transgene into their genomes. The analyses demonstrated that antisense expression of pOMT8 resulted in reductions in total COMT activity, which was correlated with reduction in the lignin content of the transgenic plants. The amount of lignin in one of the transgenic lines decreased by 62% compared with untransformed control plants.