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The kinase LYK5 is a major chitin receptor in Arabidopsis and forms a chitin-induced complex with related kinase CERK1.

Cao Y, Liang Y, Tanaka K, Nguyen CT, Jedrzejczak RP, Joachimiak A, Stacey G - Elife (2014)

Bottom Line: Chitin is a fungal microbe-associated molecular pattern recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1.Mutations in AtLYK5 resulted in a significant reduction in chitin response.The data suggest that AtLYK5 is the primary receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant immunity.

View Article: PubMed Central - PubMed

Affiliation: Division of Plant Sciences, National Center for Soybean Biotechnology, University of Missouri, Columbia, United States.

ABSTRACT
Chitin is a fungal microbe-associated molecular pattern recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1. Previous research suggested that AtCERK1 is the major chitin receptor and mediates chitin-induced signaling through homodimerization and phosphorylation. However, the reported chitin binding affinity of AtCERK1 is quite low, suggesting another receptor with high chitin binding affinity might be present. Here, we propose that AtLYK5 is the primary chitin receptor in Arabidopsis. Mutations in AtLYK5 resulted in a significant reduction in chitin response. However, AtLYK5 shares overlapping function with AtLYK4 and, therefore, Atlyk4/Atlyk5-2 double mutants show a complete loss of chitin response. AtLYK5 interacts with AtCERK1 in a chitin-dependent manner. Chitin binding to AtLYK5 is indispensable for chitin-induced AtCERK1 phosphorylation. AtLYK5 binds chitin at a much higher affinity than AtCERK1. The data suggest that AtLYK5 is the primary receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant immunity.

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Tissue-specific expression of AtCERK1, AtLYK4, and AtLYK5.(A) AtCERK1 (At3g21630), AtLYK4 (At2g23770) and AtLYK5 (At2g33580) gene expression in different developmental stages predicted by AtGenExpress Visualization Tool (AVT) . Results can also be seen at http://jsp.weigelworld.org/expviz/expviz.jsp. (B) Subcellular localization of AtLYK5 in Nicotiana bethamiana. Leaf expressing AtLYK5-GFP was stained with FM4-64 before monitoring epifluorescence signal using confocal microscopy (Left panel). Right panel showed expression of AtLYK5-GFP detected by immunoblot using anti-GFP.DOI:http://dx.doi.org/10.7554/eLife.03766.011
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fig2s2: Tissue-specific expression of AtCERK1, AtLYK4, and AtLYK5.(A) AtCERK1 (At3g21630), AtLYK4 (At2g23770) and AtLYK5 (At2g33580) gene expression in different developmental stages predicted by AtGenExpress Visualization Tool (AVT) . Results can also be seen at http://jsp.weigelworld.org/expviz/expviz.jsp. (B) Subcellular localization of AtLYK5 in Nicotiana bethamiana. Leaf expressing AtLYK5-GFP was stained with FM4-64 before monitoring epifluorescence signal using confocal microscopy (Left panel). Right panel showed expression of AtLYK5-GFP detected by immunoblot using anti-GFP.DOI:http://dx.doi.org/10.7554/eLife.03766.011

Mentions: Because AtCERK1, AtLYK5, and AtLYK4 are all involved in the chitin response, we measured their transcriptional level in different plant tissues at different plant ages using quantitative PCR (qRT-PCR). At different growth stages of 5, 10, and 20 days after germination, as well as leaf and root tissues from 20-day-old plants, the transcript levels of three genes were similar. However, in the root tissue tested, AtLYK5 expression was higher than AtCERK1 and AtLYK4, while both showed similar expression levels in roots (Figure 1H). These data are consistent with the results predicted by the AtGenExpress Visualization Tool (AVT) showing that AtLYK5 is co-expressed with AtCERK1, with some variation in the root (Figure 2—figure supplement 2 or online at http://jsp.weigelworld.org/expviz/expviz.jsp).


The kinase LYK5 is a major chitin receptor in Arabidopsis and forms a chitin-induced complex with related kinase CERK1.

Cao Y, Liang Y, Tanaka K, Nguyen CT, Jedrzejczak RP, Joachimiak A, Stacey G - Elife (2014)

Tissue-specific expression of AtCERK1, AtLYK4, and AtLYK5.(A) AtCERK1 (At3g21630), AtLYK4 (At2g23770) and AtLYK5 (At2g33580) gene expression in different developmental stages predicted by AtGenExpress Visualization Tool (AVT) . Results can also be seen at http://jsp.weigelworld.org/expviz/expviz.jsp. (B) Subcellular localization of AtLYK5 in Nicotiana bethamiana. Leaf expressing AtLYK5-GFP was stained with FM4-64 before monitoring epifluorescence signal using confocal microscopy (Left panel). Right panel showed expression of AtLYK5-GFP detected by immunoblot using anti-GFP.DOI:http://dx.doi.org/10.7554/eLife.03766.011
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4356144&req=5

fig2s2: Tissue-specific expression of AtCERK1, AtLYK4, and AtLYK5.(A) AtCERK1 (At3g21630), AtLYK4 (At2g23770) and AtLYK5 (At2g33580) gene expression in different developmental stages predicted by AtGenExpress Visualization Tool (AVT) . Results can also be seen at http://jsp.weigelworld.org/expviz/expviz.jsp. (B) Subcellular localization of AtLYK5 in Nicotiana bethamiana. Leaf expressing AtLYK5-GFP was stained with FM4-64 before monitoring epifluorescence signal using confocal microscopy (Left panel). Right panel showed expression of AtLYK5-GFP detected by immunoblot using anti-GFP.DOI:http://dx.doi.org/10.7554/eLife.03766.011
Mentions: Because AtCERK1, AtLYK5, and AtLYK4 are all involved in the chitin response, we measured their transcriptional level in different plant tissues at different plant ages using quantitative PCR (qRT-PCR). At different growth stages of 5, 10, and 20 days after germination, as well as leaf and root tissues from 20-day-old plants, the transcript levels of three genes were similar. However, in the root tissue tested, AtLYK5 expression was higher than AtCERK1 and AtLYK4, while both showed similar expression levels in roots (Figure 1H). These data are consistent with the results predicted by the AtGenExpress Visualization Tool (AVT) showing that AtLYK5 is co-expressed with AtCERK1, with some variation in the root (Figure 2—figure supplement 2 or online at http://jsp.weigelworld.org/expviz/expviz.jsp).

Bottom Line: Chitin is a fungal microbe-associated molecular pattern recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1.Mutations in AtLYK5 resulted in a significant reduction in chitin response.The data suggest that AtLYK5 is the primary receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant immunity.

View Article: PubMed Central - PubMed

Affiliation: Division of Plant Sciences, National Center for Soybean Biotechnology, University of Missouri, Columbia, United States.

ABSTRACT
Chitin is a fungal microbe-associated molecular pattern recognized in Arabidopsis by a lysin motif receptor kinase (LYK), AtCERK1. Previous research suggested that AtCERK1 is the major chitin receptor and mediates chitin-induced signaling through homodimerization and phosphorylation. However, the reported chitin binding affinity of AtCERK1 is quite low, suggesting another receptor with high chitin binding affinity might be present. Here, we propose that AtLYK5 is the primary chitin receptor in Arabidopsis. Mutations in AtLYK5 resulted in a significant reduction in chitin response. However, AtLYK5 shares overlapping function with AtLYK4 and, therefore, Atlyk4/Atlyk5-2 double mutants show a complete loss of chitin response. AtLYK5 interacts with AtCERK1 in a chitin-dependent manner. Chitin binding to AtLYK5 is indispensable for chitin-induced AtCERK1 phosphorylation. AtLYK5 binds chitin at a much higher affinity than AtCERK1. The data suggest that AtLYK5 is the primary receptor for chitin, forming a chitin inducible complex with AtCERK1 to induce plant immunity.

Show MeSH