The scientists' main finding was the discovery of three such components (called F-box proteins) that specifically recognize the first key enzyme in the series of phenol synthesis reactions. The scientists showed that these three F-box proteins interact with the enzyme (phenylalanine ammonia-lyase, or PAL), leading to its degradation.
They further demonstrated that turning on the genes encoding the F-box proteins reduced the cellular level of PAL in living plant cells. Reduced levels of PAL, in turn, resulted in lower levels of certain plant phenols.
One of the affected products was lignin, a polyphenol that is a component of plant cell walls. Lignin makes biomass particularly hard to break down and convert into liquid fuels. Plants with lower levels of lignin should be easier to convert.
"This strategy of increasing PAL degradation to reduce cell-wall lignin levels could therefore be used to make plant matter easier to break down, thereby improving the ease and efficiency of biofuel production," Liu said.
While the goal of this work was to learn how to improve plant biofuel feedstocks, knowing how to manipulate plant phenols may be useful for other goals, said Liu. For example, the set of molecular tools identified in this study might be used to increase the synthesis of certain phenols that have been shown to exhibit antioxidant properties, which could potentially enhance the health benefits of so-called functional foods.
|Contact: Karen McNulty Walsh|
DOE/Brookhaven National Laboratory