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A key general stress response motif is regulated non‐uniformly by CAMTA transcription factors
Author(s) -
Benn Geoffrey,
Wang ChangQuan,
Hicks Derrick R.,
Stein Jeffrey,
Guthrie Cade,
Dehesh Katayoon
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12620
Subject(s) - microbiology and biotechnology , transcription factor , mutant , biology , integrated stress response , arabidopsis , cellular stress response , luciferase , activator (genetics) , signal transduction , fight or flight response , biochemistry , gene , messenger rna , transfection , translation (biology)
Summary Plants cope with environmental challenges by rapidly triggering and synchronizing mechanisms governing stress‐specific and general stress response ( GSR ) networks. The GSR acts rapidly and transiently in response to various stresses, but the underpinning mechanisms have remained elusive. To define GSR regulatory components we have exploited the Rapid Stress Response Element ( RSRE ), a previously established functional GSR motif, using Arabidopsis plants expressing a 4xRSRE::Luciferase ( RSRE :: LUC ) reporter. Initially, we searched public microarray datasets and found an enrichment of RSRE in promoter sequences of stress genes. Next, we treated RSRE::LUC plants with wounding and a range of rapidly stress‐inducible hormones and detected a robust LUC activity solely in response to wounding. Application of two Ca 2+ burst inducers, flagellin22 (flg22) and oligogalacturonic acid, activated RSRE strongly and systemically, while the C a 2+ chelator ethylene glycol tetraacetic acid ( EGTA ) significantly reduced wound induction of RSRE :: LUC . In line with the signaling function of C a 2+ in transduction events leading to activation of RSRE , we examined the role of CALMODULIN‐BINDING TRANSCRIPTIONAL ACTIVATORs ( CAMTA s) in RSRE induction. Transient expression assays displayed CAMTA3 induction of RSRE and not that of the mutated element m RSRE . Treatment of selected camta mutant lines integrated into RSRE :: LUC parent plant, with wounding, flg22, and freezing, established a differential function of these CAMTA s in potentiating the activity of RSRE . Wound response studies using camta double mutants revealed a cooperative function of CAMTA s2 and 4 with CAMTA 3 in the RSRE regulation. These studies provide insights into governing components of transduction events and reveal transcriptional modules that tune the expression of a key GSR motif.