Suppression of the microRNA pathway by bacterial effector proteins.
Plants and animals sense pathogen-associated molecular patterns (PAMPs) and in turn differentially regulate a subset of microRNAs (miRNAs). However, the extent to which the miRNA pathway contributes to innate immunity remains unknown. Here, we show that miRNA-deficient mutants of Arabidopsis partly restore growth of a type III secretion-defective mutant of Pseudomonas syringae. These mutants also sustained growth of nonpathogenic Pseudomonas fluorescens and Escherichia coli strains, implicating miRNAs as key components of plant basal defense. Accordingly, we have identified P. syringae effectors that suppress transcriptional activation of some PAMP-responsive miRNAs or miRNA biogenesis, stability, or activity. These results provide evidence that, like viruses, bacteria have evolved to suppress RNA silencing to cause disease.
Navarro
Lionel
L
Institut de Biologie Moléculaire des Plantes, CNRS UPR 2353-Université Louis Pasteur, 12 Rue du Général Zimmer, 67084 Strasbourg Cedex, France.
Jay
Florence
F
Nomura
Kinya
K
He
Sheng Yang
SY
Voinnet
Olivier
O
D017360:Arabidopsis / Q000235:genetics / Q000276:immunology / Q000382:microbiology* / Q000821:virology; D001426:Bacterial Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000254:growth & development; D007113:Immunity, Innate; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology*; D018515:Plant Leaves / Q000378:metabolism / Q000382:microbiology; D030821:Plants, Genetically Modified; D017800:Potyvirus / Q000502:physiology; D011551:Pseudomonas fluorescens / Q000254:growth & development; D044224:Pseudomonas syringae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity; D034622:RNA Interference; D020871:RNA Stability; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D035683:MicroRNAs; D018749:RNA, Plant; C081695:avrPto protein, Pseudomonas syringae