Bacterial RNAs activate innate immunity in Arabidopsis.
The common molecular patterns of microbes play a critical role in the regulation of plant innate immunity. However, little is known about the role of nucleic acids in this process in plants. We pre-infiltrated Arabidopsis leaves with total RNAs from Pseudomonas syringae pv. tomato DC3000 (Pto DC3000) and subsequently inoculated these plants with the same bacterial cells. Total Pto DC3000 RNAs pre-infiltrated into Arabidopsis leaves elicited plant immune responses against Pto DC3000. However, sheared RNAs and RNase A application failed to induce immunity, suggesting that intact bacterial RNAs function in plant innate immunity. This notion was supported by the positive regulation of superoxide anion levels, callose deposition, two mitogen-activated protein kinases and defense-related genes observed in bacterial RNA-pre-treated leaves. Intriguingly, the Pto DC3000 population was not compromised in known pattern recognition receptor mutants for chitin, flagellin and elongation factor-Tu (EF-Tu). Plant defense-related mutant analyses further revealed that bacterial RNA-elicited innate immunity was normally required for salicylic and jasmonic acid signaling. Notably, among total RNAs, the abundant bacterial RNA species 16S and 23S ribosomal RNAs were the major determinants of this response. Our findings provide evidence that bacterial RNA serves as a microbe-associated molecular pattern in plants.
Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea.|Eco-friendly New Material Research Group, KRICT, Daejeon, 305-600, South Korea.
Boyoung
B
Lee
Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea.|Agricultural Microbiology Division, National Academy of Agricultural Science, Wanju, 565-851, South Korea.
Yong-Soon
YS
Park
Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea.
Soohyun
S
Lee
Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea.
Geun Cheol
GC
Song
Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea.|Biosystems and Bioengineering Program, University of Science and Technology (UST), Daejeon, 305-350, South Korea.
Choong-Min
CM
Ryu
D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics; D003517:Cyclopentanes / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D018506:Gene Expression Regulation, Plant; D007113:Immunity, Innate / Q000235:genetics*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics; D054883:Oxylipins / Q000378:metabolism; D000069452:Pathogen-Associated Molecular Pattern Molecules / Q000276:immunology; D018515:Plant Leaves / Q000276:immunology; D044224:Pseudomonas syringae / Q000235:genetics* / Q000472:pathogenicity; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D020156:Salicylic Acid / Q000378:metabolism
D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D054883:Oxylipins; D000069452:Pathogen-Associated Molecular Pattern Molecules; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; C011006:jasmonic acid; C458516:AtMPK3 protein, Arabidopsis; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D020156:Salicylic Acid
Pseudomonas syringae; bacterial RNAs; jasmonic acid (JA); microbe-associated molecular pattern (MAMP); plant innate immunity; salicylic acid (SA)