Calmodulin-binding transcription activator (CAMTA) 3 mediates biotic defense responses in Arabidopsis

Edited by Michael R. Sussman

Received 18 January 2008; received in revised form 14 February 2008; accepted 15 February 2008. published online 25 February 2008.

Abstract

Calmodulin-binding transcription activator (CAMTA) 3 (also called SR1) is a calmodulin-binding transcription factor in Arabidopsis. Two homozygous T-DNA insertion mutants (camta3-1, camta3-2) showed enhanced spontaneous lesions. Transcriptome analysis of both mutants revealed 6 genes with attenuated expression and 99 genes with elevated expression. Of the latter, 32 genes are related to defense against pathogens (e.g. WRKY33, PR1 and chitinase). Propagation of a virulent strain of the bacterial pathogen Pseudomonas syringae and the fungal pathogen Botrytis cinerea were attenuated in both mutants. Moreover, both mutants accumulated high levels of H2O2. We suggest that CAMTA3 regulates the expression of a set of genes involved in biotic defense responses.

Abbreviations: CaM, calmodulin, CAMTA, CaM-binding transcription activator, DAB, 3-diaminobenzidine, LMM, lesion mimicking mutant, ROS, reactive oxygen species, TF, transcription factor, cfu, colony forming units

Keywords: Calcium, Calmodulin, Pathogens, Reactive oxygen species, Signal transduction, Transcriptome

a Department of Plant Sciences, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel

b Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK

c Plant Stress Signalling Lab, Institute of Plant and Microbial Sciences, School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK

Corresponding author. Fax: +972 3 6406816.

1 These authors contributed equally to this work.

PII: S0014-5793(08)00145-2

doi:10.1016/j.febslet.2008.02.037

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