PARG1 and EXA1 Interacting Genes Are Important Regulators of Autoimmunity in Plants

Studies were performed on the Arabidopsis thaliana double mutant plants parg1 exa1 characterized by cell death along the leaf margin, activation of expression of immune receptor genes, PR-genes, and hypersensitive response genes, which is a sign of autoimmunity. At the same time, unlike other autoimmunity mutations, the parg1 exa1 mutant demonstrated the acquisition of pluripotency by leaf cells and the ability to regenerate new leaf margins. Because of the unusual phenotype, this study analyzed in depth the transcriptome of young leaves of mutant and wild-type plants. The mutant was found to have increased expression levels of all major components of the immune response, including genes for Ca²⁺-conducting channels, NADPH oxidases, salicylic acid synthesis genes, jasmonic acid, etc. The findings suggest that PARG1 and EXA1 genes, which control the level of poly(ADP-ribosylation) and the process of nonsense-mediated RNA decay, respectively, are important regulators of the immune response. Their function is essential to prevent overactivation of defense systems in plants.