The Arabidopsis miR396 mediates pathogen-associated molecular pattern-triggered immune responses against fungal pathogens.
MicroRNAs (miRNAs) play a pivotal role in regulating gene expression during plant development. Although a substantial fraction of plant miRNAs has proven responsive to pathogen infection, their role in disease resistance remains largely unknown, especially during fungal infections. In this study, we screened Arabidopsis thaliana lines in which miRNA activity has been reduced using artificial miRNA target mimics (MIM lines) for their response to fungal pathogens. Reduced activity of miR396 (MIM396 plants) was found to confer broad resistance to necrotrophic and hemibiotrophic fungal pathogens. MiR396 levels gradually decreased during fungal infection, thus, enabling its GRF (GROWTH-REGULATING FACTOR) transcription factor target genes to trigger host reprogramming. Pathogen resistance in MIM396 plants is based on a superactivation of defense responses consistent with a priming event during pathogen infection. Notably, low levels of miR396 are not translated in developmental defects in absence of pathogen challenge. Our findings support a role of miR396 in regulating plant immunity, and broaden our knowledge about the molecular players and processes that sustain defense priming. That miR396 modulates innate immunity without growth costs also suggests fine-tuning of miR396 levels as an effective biotechnological means for protection against pathogen infection.
Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB. Edifici CRAG, Campus UAB, Bellaterra (Cerdanyola del Vallés), 08193 Barcelona, Spain.
Mauricio
M
Soto-Suárez
Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB. Edifici CRAG, Campus UAB, Bellaterra (Cerdanyola del Vallés), 08193 Barcelona, Spain.
Patricia
P
Baldrich
Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
Detlef
D
Weigel
Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB. Edifici CRAG, Campus UAB, Bellaterra (Cerdanyola del Vallés), 08193 Barcelona, Spain.|Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
Ignacio
I
Rubio-Somoza
Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB. Edifici CRAG, Campus UAB, Bellaterra (Cerdanyola del Vallés), 08193 Barcelona, Spain.
Blanca
B
San Segundo
D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology; D060467:Disease Resistance / Q000235:genetics / Q000276:immunology; D004198:Disease Susceptibility; D005658:Fungi; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D054884:Host-Pathogen Interactions / Q000235:genetics* / Q000276:immunology*; D035683:MicroRNAs / Q000235:genetics*; D000069452:Pathogen-Associated Molecular Pattern Molecules; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D030821:Plants, Genetically Modified; D059467:Transcriptome
C572930:MIRN396 microRNA, Arabidopsis; D035683:MicroRNAs; D000069452:Pathogen-Associated Molecular Pattern Molecules