Genetic engineering of lignin biosynthesis in poplar

The removal of lignin in paper manufacture is a toxic and energy-requiring process. For the paper industry and for the environment, it would be very beneficial to process trees with less lignin or with lignin that is more easily extractable. To achieve this goal, we are down-regulating the activity of a number of lignin biosynthesis enzymes in poplar by genetic engineering and studying their role in determining the quantity and quality of lignin. Here, our recent results obtained in this field are summarized with emphasis on bispecific caffeic acid/5-OH-ferulic acid-O-methyltransferase, cinnamoyl-CoA-reductase, caffeoyl-CoA-O-methyltransferase, and peroxidase.