title: MicroRNAs suppress NB domain genes in tomato that confer resistance to Fusarium oxysporum.
abstract: MicroRNAs (miRNAs) suppress the transcriptional and post-transcriptional expression of genes in plants. Several miRNA families target genes encoding nucleotide-binding site-leucine-rich repeat (NB-LRR) plant innate immune receptors. The fungus Fusarium oxysporum f. sp. lycopersici causes vascular wilt disease in tomato. We explored a role for miRNAs in tomato defense against F. oxysporum using comparative miRNA profiling of susceptible (Moneymaker) and resistant (Motelle) tomato cultivars. slmiR482f and slmiR5300 were repressed during infection of Motelle with F. oxysporum. Two predicted mRNA targets each of slmiR482f and slmiR5300 exhibited increased expression in Motelle and the ability of these four targets to be regulated by the miRNAs was confirmed by co-expression in Nicotiana benthamiana. Silencing of the targets in the resistant Motelle cultivar revealed a role in fungal resistance for all four genes. All four targets encode proteins with full or partial nucleotide-binding (NB) domains. One slmiR5300 target corresponds to tm-2, a susceptible allele of the Tomato Mosaic Virus resistance gene, supporting functions in immunity to a fungal pathogen. The observation that none of the targets correspond to I-2, the only known resistance (R) gene for F. oxysporum in tomato, supports roles for additional R genes in the immune response. Taken together, our findings suggest that Moneymaker is highly susceptible because its potential resistance is insufficiently expressed due to the action of miRNAs.
authors.affiliation: Department of Plant Pathology and Microbiology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America.
authors.forename: Shouqiang
authors.initials: S
authors.lastname: Ouyang
authors.affiliation: Department of Plant Pathology and Microbiology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America.
authors.forename: Gyungsoon
authors.initials: G
authors.lastname: Park
authors.affiliation: Department of Nematology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America.
authors.forename: Hagop S
authors.initials: HS
authors.lastname: Atamian
authors.affiliation: Bioscience Division, MS M888, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America.
authors.forename: Cliff S
authors.initials: CS
authors.lastname: Han
authors.affiliation: Department of Plant Pathology and Microbiology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America.
authors.forename: Jason E
authors.initials: JE
authors.lastname: Stajich
authors.affiliation: Department of Nematology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America.
authors.forename: Isgouhi
authors.initials: I
authors.lastname: Kaloshian
authors.affiliation: Department of Plant Pathology and Microbiology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Borkovich
mesh_terms: D000483:Alleles; D001665:Binding Sites; D005670:Fusarium / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000821:virology*; D035683:MicroRNAs / Q000378:metabolism*; D009711:Nucleotides / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D017898:Tobamovirus
chemical_list: D035683:MicroRNAs; D009711:Nucleotides