Format

Send to

Choose Destination
Plant Cell. 2017 Oct;29(10):2465-2477. doi: 10.1105/tpc.16.00865. Epub 2017 Oct 5.

CAMTA-Mediated Regulation of Salicylic Acid Immunity Pathway Genes in Arabidopsis Exposed to Low Temperature and Pathogen Infection.

Author information

1
MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824.
2
MSU Plant Resilience Institute, Michigan State University, East Lansing, Michigan 48824.
3
Laboratory of Seed Science and Technology, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, P.R. China.
4
Department of Horticulture, Michigan State University, East Lansing, Michigan 48824.
5
MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 thomash6@msu.edu.
6
Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824.

Abstract

Arabidopsis thaliana calmodulin binding transcription activator (CAMTA) factors repress the expression of genes involved in salicylic acid (SA) biosynthesis and SA-mediated immunity in healthy plants grown at warm temperature (22°C). This repression is overcome in plants exposed to low temperature (4°C) for more than a week and in plants infected by biotrophic and hemibiotrophic pathogens. Here, we present evidence that CAMTA3-mediated repression of SA pathway genes in nonstressed plants involves the action of an N-terminal repression module (NRM) that acts independently of calmodulin (CaM) binding to the IQ and CaM binding (CaMB) domains, a finding that is contrary to current thinking that CAMTA3 repression activity requires binding of CaM to the CaMB domain. Induction of SA pathway genes in response to low temperature did not occur in plants expressing only the CAMTA3-NRM region of the protein. Mutational analysis provided evidence that the repression activity of the NRM was suppressed by action of the IQ and CaMB domains responding to signals generated in response to low temperature. Plants expressing the CAMTA3-NRM region were also impaired in defense against the bacterial hemibiotrophic pathogen Pseudomonas syringae pv tomato DC3000. Our results indicate that the regulation of CAMTA3 repression activity by low temperature and pathogen infection involves related mechanisms, but with distinct differences.

PMID:
28982964
PMCID:
PMC5774559
DOI:
10.1105/tpc.16.00865
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center