An Arabidopsis mutant cex1 exhibits constant accumulation of jasmonate-regulated ArVSP, Thi2.1 and PDF1.2

Jasmonates (JA) act as a regulator in plant growth as well as a signal in p lant defense. The Arabidopsis vegetative storage protein (AtVSP) and plant defense-related proteins thionin (Thi2.1) and defensin (PDF1.2) have previo usly been shown to accumulate in response to JA induction. In this report, we isolated and characterized a novel recessive mutant, cex1, conferring co nstitutive JA-responsive phenotypes including JA-inhibitory growth and cons titutive expression of JA-regulated AtYSP, Thi2.1 and PDF1.2. The plant mor phology and the gene expression pattern of the cex1 mutant could be phenoco pied by treatment of wild-type plants with exogenous JA, indicating that CE X1 might be a negative regulator of the JA response pathway. (C) 2001 Publi shed by Elsevier Science B.V. on behalf of the Federation of European Bioch emical Societies.