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.
['Lee|Boyoung|B|', 'Park|Yong-Soon|YS|', 'Lee|Soohyun|S|', 'Song|Geun Cheol|GC|', 'Ryu|Choong-Min|CM|']
D017360:Arabidopsis D029681:Arabidopsis Proteins D003517:Cyclopentanes D004578:Electron Spin Resonance Spectroscopy D018506:Gene Expression Regulation, Plant D007113:Immunity, Innate D020929:Mitogen-Activated Protein Kinase Kinases D020928:Mitogen-Activated Protein Kinases D054883:Oxylipins D000069452:Pathogen-Associated Molecular Pattern Molecules D018515:Plant Leaves D044224:Pseudomonas syringae D012329:RNA, Bacterial D012336:RNA, Ribosomal, 16S D012338:RNA, Ribosomal, 23S D020156:Salicylic Acid
bacterial RNAs plant innate immunity Pseudomonas syringae jasmonic acid (JA) microbe-associated molecular pattern (MAMP) salicylic acid (SA)