Two LysM receptor molecules, CEBiP and OsCERK1, cooperatively regulate chitin elicitor signaling in rice.
Chitin is a major molecular pattern for various fungi, and its fragments, chitin oligosaccharides, are known to induce various defense responses in plant cells. A plasma membrane glycoprotein, CEBiP (chitin elicitor binding protein) and a receptor kinase, CERK1 (chitin elicitor receptor kinase) (also known as LysM-RLK1), were identified as critical components for chitin signaling in rice and Arabidopsis, respectively. However, it is not known whether each plant species requires both of these two types of molecules for chitin signaling, nor the relationships between these molecules in membrane signaling. We report here that rice cells require a LysM receptor-like kinase, OsCERK1, in addition to CEBiP, for chitin signaling. Knockdown of OsCERK1 resulted in marked suppression of the defense responses induced by chitin oligosaccharides, indicating that OsCERK1 is essential for chitin signaling in rice. The results of a yeast two-hybrid assay indicated that both CEBiP and OsCERK1 have the potential to form hetero- or homo-oligomers. Immunoprecipitation using a membrane preparation from rice cells treated with chitin oligosaccharides suggested the ligand-induced formation of a receptor complex containing both CEBiP and OsCERK1. Blue native PAGE and chemical cross-linking experiments also suggested that a major portion of CEBiP exists as homo-oligomers even in the absence of chitin oligosaccharides.
Department of Life Sciences, Faculty of Agriculture, Meiji University, Kawasaki, Kanagawa, Japan.
Takeo
T
Shimizu
Takuto
T
Nakano
Daisuke
D
Takamizawa
Yoshitake
Y
Desaki
Naoko
N
Ishii-Minami
Yoko
Y
Nishizawa
Eiichi
E
Minami
Kazunori
K
Okada
Hisakazu
H
Yamane
Hanae
H
Kaku
Naoto
N
Shibuya
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002686:Chitin / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology* / Q000235:genetics; D010940:Plant Proteins / Q000378:metabolism*; D055503:Protein Multimerization; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques
D010940:Plant Proteins; D002686:Chitin; D017346:Protein Serine-Threonine Kinases