Effects of overexpression of FERULOYL-COA 6-HYDROXYLASE1 on phenolic metabolism and lignin characteristics in transgenic hybrid aspen

In this study, the same F6H1 construct has been introduced into hybrid aspen (Populus tremula Ã? tremuloides), and its effects on plant morphology, lignin chemical structure, and phenolic metabolism were examined. The resultant transgenic plants successfully overproduced scopoletin and some of them showed a severe growth retardation not seen in Arabidopsis. The accumulation seemed to be more pronounced in secondary walls of tracheary element and compound middle lamella, and somewhat lesser in fiber cell walls. Two dimensional NMR revealed that scopoletin in the cell walls is bound to lignin, leading to a reduction in lignin content, and changes in its monomeric composition and molar mass distribution. Furthermore, enzyme saccharification efficiency of the transgenic cell walls was increased more than 3 times higher than that of the wild-type plant, even without any pretreatment.