DNA constructs comprising a first DNA segment that corresponds to at least a portion of a gene in the monolignol biosynthetic pathway, a spacer DNA segment, and a second DNA segment that is complementary to the first DNA segment can be used to reduce or modulate the lignin content in plants. In some embodiments, DNA constructs comprise at least a portion of a gene for 4CL, C3H, CCR, C4H or CCoAOMT. Vascular-preferred and constitutive promoters can be used to drive expression of the constructs.