Abstract: Disclosed is a novel method of suppressing plant gene expression. The suppression is achieved by transforming a plant with a DNA construct encoding a processing-defective RNA (pd-RNA constructs). A pd-RNA construct comprises a plant active promoter operably linked to a pd-RNA encoding segment (pd-RNA segment), wherein the pd-RNA segment comprises a sequence substantially homologous to the target gene and a defective intron and/or a defective 3' termination and processing sequence (hereinafter 3' processing sequence). The pd-RNA constructs of the present invention are designed to express target-gene-homologous RNA transcripts that are defective for messenger RNA processing. Various types of pd-RNA constructs are disclosed, including those defective for endonucleolytic cleavage or polyadenylation at the 3' end of the pd-RNA transcript and/or intron splicing. A pd-RNA construct of the invention may used to suppress a single, specific target gene or multiple target genes.