Selective Control of Lignin Biosynthesis in Transgenic Plants

Background: Lignin biosynthesis control is a much sought-after objective in forest products and paper production, in grain quality improvement and in many other crops. Unfortunately, rational control of lignin biosynthesis has proved elusive. Alteration of the first enzyme in the pathway, phenylalanine-ammonia lyase (PAL) has not proven practical due to the role of this enzyme in many aromatic pathways. Conventional genetic techniques have proven only partially successful in altering lignin content of plants. This approach is too slow to be practical in trees, especially. There has been no report of practical alteration of the lignin pathway starting with the first committed enzyme, cinnamoyl CoA reductase, using either transgenic or genetic approaches.

Technology Description : We have found that a key gene, not previously thought to be involved, plays a central role in regulating lignin accumulation within plant cells. Specifically, mutants in this gene produce excess lignins in "ectopic" positions, while transgene constructs incorporating a constitutive promotor nearly abolish lignin biosynthesis. Furthermore, we have found that certain cells that would normally become lignified show a complete absence of lignin in double mutants for this and a related gene, suggesting that these two genes act redundantly to positively regulate lignin production. These results suggest that these genes can be used to regulate lignification of plant cells.

Advantages: This approach provides greatly improved selectivity and specificity in controlling lignin content without harming normal growth and reproduction, or interfering with fruiting body or seed production. This combination of traits has heretofore not been achieved.

Case Number : SD1998-117

Inquiries To : invent@ucsd.edu