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Plant Cell. 2016 Jan;28(1):102-29. doi: 10.1105/tpc.15.00496. Epub 2015 Dec 15.

Pipecolic Acid Orchestrates Plant Systemic Acquired Resistance and Defense Priming via Salicylic Acid-Dependent and -Independent Pathways.

Author information

1
Institute for Molecular Ecophysiology of Plants, Department of Biology, Heinrich Heine University, D-40225 Düsseldorf, Germany.
2
Institute for Plant Biochemistry, Department of Biology, Heinrich Heine University, D-40225 Düsseldorf, Germany Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, D-40225 Düsseldorf, Germany.
3
Institute for Molecular Ecophysiology of Plants, Department of Biology, Heinrich Heine University, D-40225 Düsseldorf, Germany Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, D-40225 Düsseldorf, Germany juergen.zeier@uni-duesseldorf.de.

Abstract

We investigated the relationships of the two immune-regulatory plant metabolites, salicylic acid (SA) and pipecolic acid (Pip), in the establishment of plant systemic acquired resistance (SAR), SAR-associated defense priming, and basal immunity. Using SA-deficient sid2, Pip-deficient ald1, and sid2 ald1 plants deficient in both SA and Pip, we show that SA and Pip act both independently from each other and synergistically in Arabidopsis thaliana basal immunity to Pseudomonas syringae. Transcriptome analyses reveal that SAR establishment in Arabidopsis is characterized by a strong transcriptional response systemically induced in the foliage that prepares plants for future pathogen attack by preactivating multiple stages of defense signaling and that SA accumulation upon SAR activation leads to the downregulation of photosynthesis and attenuated jasmonate responses systemically within the plant. Whereas systemic Pip elevations are indispensable for SAR and necessary for virtually the whole transcriptional SAR response, a moderate but significant SA-independent component of SAR activation and SAR gene expression is revealed. During SAR, Pip orchestrates SA-dependent and SA-independent priming of pathogen responses in a FLAVIN-DEPENDENT-MONOOXYGENASE1 (FMO1)-dependent manner. We conclude that a Pip/FMO1 signaling module acts as an indispensable switch for the activation of SAR and associated defense priming events and that SA amplifies Pip-triggered responses to different degrees in the distal tissue of SAR-activated plants.

PMID:
26672068
PMCID:
PMC4746677
DOI:
10.1105/tpc.15.00496
[Indexed for MEDLINE]
Free PMC Article

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