Infection of potato leaves by the pathogens Phytophthora infestans and Pseudomonas syringae leads to elevated transcription of DES and accumulation of the 9-divinyl ethers (DVEs) colneleic acid and colnelenic acid (CA and CnA, respectively; Weber et al., 1999; Stumpe et al., 2001). This evidence concerns the gene PPP3CA and infection.