Analysis of flagellin perception mediated by flg22 receptor OsFLS2 in rice.
Plants have sensitive perception systems that recognize various pathogen-derived molecules. We previously reported that rice detects flagellin from a rice-incompatible strain of gram-negative phytopathogenic bacterium, Acidovorax avenae, which induces subsequent immune responses involving cell death. The mechanism of flagellin perception in rice, however, has remained obscure. In this study, we found that flg22, a peptide derived from the flagellin N-terminus, induced weak immune responses without cell death in cultured rice cells. To elucidate the mechanism by which flg22 induced signaling in rice, we characterized OsFLS2, the rice ortholog of AtFLS2, which mediates flg22 perception. Heterologous expression of OsFLS2 functions in Arabidopsis, showing the conservation of the flg22 signaling pathway across divergent plant taxa. OsFLS2-overexpressing rice cultured cells generated stronger immune responses with the induction of cell death following stimulation with flg22 and flagellin. However, examination of the growth rate of the compatible strain in inoculated OsFLS2-overexpressing rice could not confirm bacterial growth suppression compared with wild-type rice. These results suggest that rice possesses a conserved flagellin perception system utilizing the FLS2 receptor which, when upregulated, hardly affects resistance against compatible A. avenae.
Takai
Ryota
R
Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), 8916-5, Takayama Ikoma, Nara 630-0191, Japan.
Isogai
Akira
A
Takayama
Seiji
S
Che
Fang-Sik
FS
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D016923:Cell Death; D002478:Cells, Cultured; D042621:Comamonadaceae / Q000276:immunology / Q000472:pathogenicity; D005408:Flagellin / Q000276:immunology / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D007113:Immunity, Innate; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D016415:Sequence Alignment; D013379:Substrate Specificity; D014170:Transformation, Genetic
D029681:Arabidopsis Proteins; D010940:Plant Proteins; D018749:RNA, Plant; D005408:Flagellin; D006861:Hydrogen Peroxide; D011494:Protein Kinases; C411853:FLS2 protein, Arabidopsis