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Genomic screens identify a new phytobacterial microbe-associated molecular pattern and the cognate Arabidopsis receptor-like kinase that mediates its immune elicitation.

Mott GA, Thakur S, Smakowska E, Wang PW, Belkhadir Y, Desveaux D, Guttman DS - Genome Biol. (2016)

Bottom Line: We test the six elicitors on 187 receptor-like kinase knock-down insertion lines using a high-throughput peroxidase-based immune assay and identify multiple lines that show decreased immune responses to specific peptides.These results identify xup25 as a P. syringae microbe-associated molecular pattern and xanthine/uracil permease sensing 1 as a receptor-like kinase that detects the xup25 epitope to activate immune responses.The present study demonstrates an efficient method to identify immune elicitors and the plant receptors responsible for their perception.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, Ontario, Canada.

ABSTRACT

Background: The recognition of microbe-associated molecular patterns during infection is central to the mounting of an effective immune response. In spite of their importance, it remains difficult to identify these molecules and the host receptors required for their perception, ultimately limiting our understanding of the role of these molecules in the evolution of host-pathogen relationships.

Results: We employ a comparative genomics screen to identify six new immune eliciting peptides from the phytopathogenic bacterium Pseudomonas syringae. We then perform a reverse genetic screen to identify Arabidopsis thaliana leucine-rich repeat receptor-like kinases required for the recognition of these elicitors. We test the six elicitors on 187 receptor-like kinase knock-down insertion lines using a high-throughput peroxidase-based immune assay and identify multiple lines that show decreased immune responses to specific peptides. From this primary screen data, we focused on the interaction between the xup25 peptide from a bacterial xanthine/uracil permease and the Arabidopsis receptor-like kinase xanthine/uracil permease sensing 1; a family XII protein closely related to two well-characterized receptor-like kinases. We show that xup25 treatment increases pathogenesis-related gene induction, callose deposition, seedling growth inhibition, and resistance to virulent bacteria, all in a xanthine/uracil permease sensing 1-dependent manner. Finally, we show that this kinase-like receptor can bind the xup25 peptide directly. These results identify xup25 as a P. syringae microbe-associated molecular pattern and xanthine/uracil permease sensing 1 as a receptor-like kinase that detects the xup25 epitope to activate immune responses.

Conclusions: The present study demonstrates an efficient method to identify immune elicitors and the plant receptors responsible for their perception. Further exploration of these molecules will increase our understanding of plant-pathogen interactions and the basis for host specificity.

No MeSH data available.


Related in: MedlinePlus

Arabidopsis thaliana PRRs form a single phylogenetic cluster within a maximum likelihood phylogeny of LRR-RLKs. a Maximum likelihood phylogenetic analysis of A. thaliana LRR-RLKs. A total of 187 T-DNA lines, representing 169 genes (red circles) were screened for response to the six candidate elicitors. The clade containing FLS2, EFR, and XPS1 (blue circle) is highlighted in blue. b Maximum likelihood phylogenetic analysis of A. thaliana LRR-RLKs in the XII family, which contains XPS1. This clade includes FLS2 and EFR, which recognize flagellin (flg22 peptide MAMP) and EF-Tu (elf18 peptide MAMP), respectively
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Fig2: Arabidopsis thaliana PRRs form a single phylogenetic cluster within a maximum likelihood phylogeny of LRR-RLKs. a Maximum likelihood phylogenetic analysis of A. thaliana LRR-RLKs. A total of 187 T-DNA lines, representing 169 genes (red circles) were screened for response to the six candidate elicitors. The clade containing FLS2, EFR, and XPS1 (blue circle) is highlighted in blue. b Maximum likelihood phylogenetic analysis of A. thaliana LRR-RLKs in the XII family, which contains XPS1. This clade includes FLS2 and EFR, which recognize flagellin (flg22 peptide MAMP) and EF-Tu (elf18 peptide MAMP), respectively

Mentions: Having identified a set of elicitors that induced a robust and reproducible immune response in A. thaliana ecotypes Col-0 and WS using the POX assay, we set out to identify plant LRR-RLKs required for the perception of these peptides. We identified a candidate list of A. thaliana ecotype Col-0 LRR-RLKs by searching the A. thaliana protein database for all proteins containing both an LRR and a kinase domain; recovering 227 proteins containing both domains, of which 216 also contain predicted transmembrane domains (Additional file 1: Table S5 and Fig. 2a, similar to previously published studies [9, 11]). We obtained 187 T-DNA insertional mutants representing 169 of the LRR-RLK encoding genes (several lines had T-DNA insertions in the same gene; Fig. 2a).Fig. 2


Genomic screens identify a new phytobacterial microbe-associated molecular pattern and the cognate Arabidopsis receptor-like kinase that mediates its immune elicitation.

Mott GA, Thakur S, Smakowska E, Wang PW, Belkhadir Y, Desveaux D, Guttman DS - Genome Biol. (2016)

Arabidopsis thaliana PRRs form a single phylogenetic cluster within a maximum likelihood phylogeny of LRR-RLKs. a Maximum likelihood phylogenetic analysis of A. thaliana LRR-RLKs. A total of 187 T-DNA lines, representing 169 genes (red circles) were screened for response to the six candidate elicitors. The clade containing FLS2, EFR, and XPS1 (blue circle) is highlighted in blue. b Maximum likelihood phylogenetic analysis of A. thaliana LRR-RLKs in the XII family, which contains XPS1. This clade includes FLS2 and EFR, which recognize flagellin (flg22 peptide MAMP) and EF-Tu (elf18 peptide MAMP), respectively
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4862170&req=5

Fig2: Arabidopsis thaliana PRRs form a single phylogenetic cluster within a maximum likelihood phylogeny of LRR-RLKs. a Maximum likelihood phylogenetic analysis of A. thaliana LRR-RLKs. A total of 187 T-DNA lines, representing 169 genes (red circles) were screened for response to the six candidate elicitors. The clade containing FLS2, EFR, and XPS1 (blue circle) is highlighted in blue. b Maximum likelihood phylogenetic analysis of A. thaliana LRR-RLKs in the XII family, which contains XPS1. This clade includes FLS2 and EFR, which recognize flagellin (flg22 peptide MAMP) and EF-Tu (elf18 peptide MAMP), respectively
Mentions: Having identified a set of elicitors that induced a robust and reproducible immune response in A. thaliana ecotypes Col-0 and WS using the POX assay, we set out to identify plant LRR-RLKs required for the perception of these peptides. We identified a candidate list of A. thaliana ecotype Col-0 LRR-RLKs by searching the A. thaliana protein database for all proteins containing both an LRR and a kinase domain; recovering 227 proteins containing both domains, of which 216 also contain predicted transmembrane domains (Additional file 1: Table S5 and Fig. 2a, similar to previously published studies [9, 11]). We obtained 187 T-DNA insertional mutants representing 169 of the LRR-RLK encoding genes (several lines had T-DNA insertions in the same gene; Fig. 2a).Fig. 2

Bottom Line: We test the six elicitors on 187 receptor-like kinase knock-down insertion lines using a high-throughput peroxidase-based immune assay and identify multiple lines that show decreased immune responses to specific peptides.These results identify xup25 as a P. syringae microbe-associated molecular pattern and xanthine/uracil permease sensing 1 as a receptor-like kinase that detects the xup25 epitope to activate immune responses.The present study demonstrates an efficient method to identify immune elicitors and the plant receptors responsible for their perception.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, Ontario, Canada.

ABSTRACT

Background: The recognition of microbe-associated molecular patterns during infection is central to the mounting of an effective immune response. In spite of their importance, it remains difficult to identify these molecules and the host receptors required for their perception, ultimately limiting our understanding of the role of these molecules in the evolution of host-pathogen relationships.

Results: We employ a comparative genomics screen to identify six new immune eliciting peptides from the phytopathogenic bacterium Pseudomonas syringae. We then perform a reverse genetic screen to identify Arabidopsis thaliana leucine-rich repeat receptor-like kinases required for the recognition of these elicitors. We test the six elicitors on 187 receptor-like kinase knock-down insertion lines using a high-throughput peroxidase-based immune assay and identify multiple lines that show decreased immune responses to specific peptides. From this primary screen data, we focused on the interaction between the xup25 peptide from a bacterial xanthine/uracil permease and the Arabidopsis receptor-like kinase xanthine/uracil permease sensing 1; a family XII protein closely related to two well-characterized receptor-like kinases. We show that xup25 treatment increases pathogenesis-related gene induction, callose deposition, seedling growth inhibition, and resistance to virulent bacteria, all in a xanthine/uracil permease sensing 1-dependent manner. Finally, we show that this kinase-like receptor can bind the xup25 peptide directly. These results identify xup25 as a P. syringae microbe-associated molecular pattern and xanthine/uracil permease sensing 1 as a receptor-like kinase that detects the xup25 epitope to activate immune responses.

Conclusions: The present study demonstrates an efficient method to identify immune elicitors and the plant receptors responsible for their perception. Further exploration of these molecules will increase our understanding of plant-pathogen interactions and the basis for host specificity.

No MeSH data available.


Related in: MedlinePlus