Abstract: The present invention related to nucleic acid molecules corresponding to regulatory portions of genes whose expression is predominant in cambium and/or xylem. The invention also relates to compositions and methods of using the same to regulate the expression, in a cambium/xylem-preferred manner, of genes and/or any kind of nucleotide sequences in a plant. Nucleic acid molecules and its compositions include novel nucleotide sequences for cambium/xylem-preferred promoters identified and isolated from poplar (Populus spp). Methods for expressing genes and/or any kind of nucleotide sequences in a plant using the promoter sequences disclosed herein are provided. The methods comprise stably incorporating into the genome of a plant cell a nucleotide sequence operably linked to a cambium/xylem-preferred promoter of the present invention and regenerating a stably transformed plant that expresses the nucleotide sequence.

Abstract: In angiosperm and gymnosperm plants, overexpressing a SAMdc nucleotide sequence can decrease lignin content and, for plants with woody tissue, increase wood density.