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 a least a portion of a gene for 4CL, C3H, CCR, C4H, Cald5H, 5AD or CCoAOMT. Vascular-preferred and constitutive promoters can be used to drive expression of the constructs.