A lectin receptor kinase as a potential sensor for extracellular nicotinamide adenine dinucleotide in Arabidopsis thaliana
- University of Florida, United States
- GlaxoSmithKline, United States
Abstract
Nicotinamide adenine dinucleotide (NAD+) participates in intracellular and extracellular signaling events unrelated to metabolism. In animals, purinergic receptors are required for extracellular NAD+ (eNAD+) to evoke biological responses, indicating that eNAD+ may be sensed by cell-surface receptors. However, the identity of eNAD+-binding receptors still remains elusive. Here, we identify a lectin receptor kinase (LecRK), LecRK-I.8, as a potential eNAD+ receptor in Arabidopsis. The extracellular lectin domain of LecRK-I.8 binds NAD+ with a dissociation constant of 436.5 104.8 nM, although much higher concentrations are needed to trigger in vivo responses. Mutations in LecRK-I.8 inhibit NAD+-induced immune responses, whereas overexpression of LecRK-I.8 enhances the Arabidopsis response to NAD+. Furthermore, LecRK-I.8 is required for basal resistance against bacterial pathogens, substantiating a role for eNAD+ in plant immunity. Our results demonstrate that lectin receptors can potentially function as eNAD+-binding receptors and provide direct evidence for eNAD+ being an endogenous signaling molecule in plants.
Data availability
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Microarray analysis of exogenous NAD+-induced transcriptome changes in Arabidopsis thalianaPublicly available at the NCBI Gene Expression Omnibus (accession no: GSE76568).
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Microarray analysis of Atelp2, npr1 and wild type (Col-0) infected with the avirulent bacterial pathogen Pst DC3000/avrRpt2Publicly available at the NCBI Gene Expression Omnibus (accession no: GSE38986).
Article and author information
Author details
Funding
National Science Foundation (IOS-0842716)
- Zhonglin Mou
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Thorsten Nürnberger, University of Tubingen, Germany
Version history
- Received: January 25, 2017
- Accepted: July 18, 2017
- Accepted Manuscript published: July 19, 2017 (version 1)
- Version of Record published: August 17, 2017 (version 2)
Copyright
© 2017, Wang et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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A lectin receptor kinase as a potential sensor for extracellular nicotinamide adenine dinucleotide in Arabidopsis thaliana
eLife 6:e25474.
https://doi.org/10.7554/eLife.25474
Further reading
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- Microbiology and Infectious Disease
- Plant Biology
Purinergic signaling activated by extracellular nucleotides and their derivative nucleosides trigger sophisticated signaling networks. The outcome of these pathways determine the capacity of the organism to survive under challenging conditions. Both extracellular ATP (eATP) and Adenosine (eAdo) act as primary messengers in mammals, essential for immunosuppressive responses. Despite the clear role of eATP as a plant damage-associated molecular pattern, the function of its nucleoside, eAdo, and of the eAdo/eATP balance in plant stress response remain to be fully elucidated. This is particularly relevant in the context of plant-microbe interaction, where the intruder manipulates the extracellular matrix. Here, we identify Ado as a main molecule secreted by the vascular fungus Fusarium oxysporum. We show that eAdo modulates the plant's susceptibility to fungal colonization by altering the eATP-mediated apoplastic pH homeostasis, an essential physiological player during the infection of this pathogen. Our work indicates that plant pathogens actively imbalance the apoplastic eAdo/eATP levels as a virulence mechanism.
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- Plant Biology
- Structural Biology and Molecular Biophysics
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