 RNAi has been used to genetically engineer plants to produce lower levels of natural plant toxins . Such techniques take advantage of the stable and heritable RNAi phenotype in plant stocks . Cotton seeds are rich in dietary protein but naturally contain the toxic terpenoid product gossypol , making them unsuitable for human consumption . RNAi has been used to produce cotton stocks whose seeds contain reduced levels of delta @-@ cadinene synthase , a key enzyme in gossypol production , without affecting the enzyme 's production in other parts of the plant , where gossypol is itself important in preventing damage from plant pests . Similar efforts have been directed toward the reduction of the cyanogenic natural product linamarin in cassava plants . 
