title: Plant cells recognize chitin fragments for defense signaling through a plasma membrane receptor.
abstract: Chitin is a major component of fungal cell walls and serves as a molecular pattern for the recognition of potential pathogens in the innate immune systems of both plants and animals. In plants, chitin oligosaccharides have been known to induce various defense responses in a wide range of plant cells including both monocots and dicots. To clarify the molecular machinery involved in the perception and transduction of chitin oligosaccharide elicitor, a high-affinity binding protein for this elicitor was isolated from the plasma membrane of suspension-cultured rice cells. Characterization of the purified protein, CEBiP, as well as the cloning of the corresponding gene revealed that CEBiP is actually a glycoprotein consisting of 328 amino acid residues and glycan chains. CEBiP was predicted to have a short membrane spanning domain at the C terminus. Knockdown of CEBiP gene by RNA interference resulted in the suppression of the elicitor-induced oxidative burst as well as the gene responses, showing that CEBiP plays a key role in the perception and transduction of chitin oligosaccharide elicitor in the rice cells. Structural analysis of CEBiP also indicated the presence of two LysM motifs in the extracellular portion of CEBiP. As the LysM motif has been known to exist in the putative Nod-factor receptor kinases involved in the symbiotic signaling between leguminous plants and rhizobial bacteria, the result indicates the involvement of partially homologous plasma membrane proteins both in defense and symbiotic signaling in plant cells.
authors.affiliation: Department of Biochemistry, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan. kaku@isc.meiji.ac.jp
authors.forename: Hanae
authors.initials: H
authors.lastname: Kaku
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nishizawa
authors.forename: Naoko
authors.initials: N
authors.lastname: Ishii-Minami
authors.forename: Chiharu
authors.initials: C
authors.lastname: Akimoto-Tomiyama
authors.forename: Naoshi
authors.initials: N
authors.lastname: Dohmae
authors.forename: Koji
authors.initials: K
authors.lastname: Takio
authors.forename: Eiichi
authors.initials: E
authors.lastname: Minami
authors.forename: Naoto
authors.initials: N
authors.lastname: Shibuya
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects*; D002686:Chitin / Q000494:pharmacology*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D034622:RNA Interference; D016415:Sequence Alignment; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D018076:DNA, Complementary; D008565:Membrane Proteins; D010940:Plant Proteins; D002686:Chitin