DEAR1, an EAR-motif-containing transcriptional repressor of DREB protein regulate plant defense and cold responses

Abstract

To examine mechanisms involved in HR-induced cell death, FOX hunting system was used to isolate gain-of-function mutants. The isolated overexpressor, which shows constitutive cell death on rosette-leaves and accelerated leaf senescence, is caused by over-expression of the DEAR1 (DREB and EAR motif protein) gene encoding transcriptional repressor that contains a the DREB domain and EAR motif.
Expression of DEAR1 was enhanced by pathogen infections. The overexpressor showed transcriptional promotion of PR genes and highly accumulation of endogenous SA. These results indicate that the SA-dependent defense pathway is activated in the overexpressor, leading to the HR-like cell death phenotype. Expression of DEAR1 is also induced by cold treatment. Transcriptional repression of the cold tolerance genes in the overexpressor results in reduction of cold tolerance. These results indicate that the DEAR1 is a key regulator for cross-talk between biotic (pathogen tolerance) and abiotic (cold tolerance) stress responses.