Rapid transcriptome changes induced by cytosolic Ca2+ transients reveal ABRE-related sequences as Ca2+-responsive cis elements in Arabidopsis.
The regulation of gene expression by cellular calcium is crucial for plant defense against biotic and abiotic stresses. However, the number of genes known to respond to specific transient calcium signals is limited, and as yet there is no definition of a calcium-responsive cis element in plants. Here, we generated specific cytosolic calcium transients in intact Arabidopsis thaliana seedlings and linked them to early transcriptome changes, followed by bioinformatic analysis of the responsive genes. A cytosolic calcium transient induced by calmodulin antagonists and blocked by lanthanides was characterized using aequorin-based luminometry and photon imaging. Analysis of transcriptome changes revealed 230 calcium-responsive genes, of which 162 were upregulated and 68 were downregulated. These include known early stress-responsive genes as well as genes of unknown function. Analysis of their upstream regions revealed, exclusively in the upregulated genes, a highly significant occurrence of a consensus sequence (P < 10(-13)) comprising two abscisic acid-specific cis elements: the abscisic acid-responsive element (ABRE; CACGTG[T/C/G]) and its coupling element ([C/A]ACGCG[T/C/G]) [corrected] Finally, we show that a tetramer of the ABRE cis element is sufficient to confer transcriptional activation in response to cytosolic Ca(2+) transients. Thus, at least for some specific Ca(2+) transients and motif combinations, ABREs function as Ca(2+)-responsive cis elements.
Kaplan
Boaz
B
Department of Plant Sciences, Weizman Institute of Science, Rehovot 76100, Israel.
Davydov
Olga
O
Knight
Heather
H
Galon
Yael
Y
Knight
Marc R
MR
Fluhr
Robert
R
Fromm
Hillel
H
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling; D002147:Calmodulin / Q000037:antagonists & inhibitors; D003600:Cytosol / Q000187:drug effects* / Q000378:metabolism; D017931:DNA Primers; D017343:Genes, Plant; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid
D002121:Calcium Channel Blockers; D002147:Calmodulin; D017931:DNA Primers; D012333:RNA, Messenger; D002118:Calcium