Biosynthesis of monolignols. Genomic and reverse genetic approaches

The biosynthesis of monolignols is one of the most studied pathways of plant natural product biosynthesis. However, the pathway has recently undergone considerable revision, and it would appear that our understanding of the exact routes for synthesis of the building blocks of lignin and lignans is still not fully understood. Early studies of in vitro enzyme specificity failed to appreciate the catalytic promiscuity of some of the enzymes of the monolignol pathway, and the evolving model of a metabolic grid for monolignol biosynthesis may fail to appreciate the possible extent of metabolic channeling within the pathway. New approaches to the study of monolignol biosynthesis include genomics, advanced cellular imaging techniques, and transgenic manipulation. This article summarizes the use of these approaches to gain a better understanding of the operation of a complex metabolic pathway.