A LysM receptor-like kinase plays a critical role in chitin signaling and fungal resistance in Arabidopsis.
Chitin, a polymer of N-acetyl-d-glucosamine, is found in fungal cell walls but not in plants. Plant cells can perceive chitin fragments (chitooligosaccharides) leading to gene induction and defense responses. We identified a LysM receptor-like protein (LysM RLK1) required for chitin signaling in Arabidopsis thaliana. The mutation in this gene blocked the induction of almost all chitooligosaccharide-responsive genes and led to more susceptibility to fungal pathogens but had no effect on infection by a bacterial pathogen. Additionally, exogenously applied chitooligosaccharides enhanced resistance against both fungal and bacterial pathogens in the wild-type plants but not in the mutant. Together, our data indicate that LysM RLK1 is essential for chitin signaling in plants (likely as part of the receptor complex) and is involved in chitin-mediated plant innate immunity. The LysM RLK1-mediated chitin signaling pathway is unique, but it may share a conserved downstream pathway with the FLS2/flagellin- and EFR/EF-Tu-mediated signaling pathways. Additionally, our work suggests a possible evolutionary relationship between the chitin and Nod factor perception mechanisms due to the similarities between their potential receptors and between the signal molecules perceived by them.
Wan
Jinrong
J
Division of Plant Sciences, National Center for Soybean Biotechnology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA.
Zhang
Xue-Cheng
XC
Neece
David
D
Ramonell
Katrina M
KM
Clough
Steve
S
Kim
Sung-Yong
SY
Stacey
Minviluz G
MG
Stacey
Gary
G
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001203:Ascomycota / Q000254:growth & development; D001419:Bacteria / Q000254:growth & development; D002686:Chitin / Q000378:metabolism*; D007887:Fabaceae / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005816:Genetic Complementation Test; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D009844:Oligosaccharides / Q000737:chemistry / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D015533:Transcriptional Activation
D029681:Arabidopsis Proteins; D009844:Oligosaccharides; D010940:Plant Proteins; D002686:Chitin