Compositions and methods for efficiently producing and delivering double stranded RNA (dsRNA) are provided. Vector constructs useful for in vitro and in vivo expression of dsRNA are described. Also described are cell expression systems for efficient and cost-effective production of dsRNA in living cells and methods and compositions for providing the expressed dsRNA to target organisms. The described compositions and methods can be used to produce RNA molecules for screening or other uses, and to amplify RNA sequences for analysis.