title: Aberrant growth and lethality of Arabidopsis deficient in nonsense-mediated RNA decay factors is caused by autoimmune-like response.
abstract: Nonsense-mediated RNA decay (NMD) is an evolutionarily conserved RNA quality control mechanism that eliminates transcripts containing nonsense mutations. NMD has also been shown to affect the expression of numerous genes, and inactivation of this pathway is lethal in higher eukaryotes. However, despite relatively detailed knowledge of the molecular basis of NMD, our understanding of its physiological functions is still limited and the underlying causes of lethality are unknown. In this study, we examined the importance of NMD in plants by analyzing an allelic series of Arabidopsis thaliana mutants impaired in the core NMD components SMG7 and UPF1. We found that impaired NMD elicits a pathogen defense response which appears to be proportional to the extent of NMD deficiency. We also demonstrate that developmental aberrations and lethality of the strong smg7 and upf1 alleles are caused by constitutive pathogen response upregulation. Disruption of pathogen signaling suppresses the lethality of the upf1-3 null allele and growth defects associated with SMG7 dysfunction. Interestingly, infertility and abortive meiosis observed in smg7 mutants is not coupled with impaired NMD suggesting a broader function of SMG7 in cellular metabolism. Taken together, our results uncover a major physiological consequence of NMD deficiency in Arabidopsis and revealed multifaceted roles of SMG7 in plant growth and development.
authors.affiliation: Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
authors.forename: Nina
authors.initials: N
authors.lastname: Riehs-Kearnan
authors.forename: Jiradet
authors.initials: J
authors.lastname: Gloggnitzer
authors.forename: Bettina
authors.initials: B
authors.lastname: Dekrout
authors.forename: Claudia
authors.initials: C
authors.lastname: Jonak
authors.forename: Karel
authors.initials: K
authors.lastname: Riha
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000276:immunology; D029681:Arabidopsis Proteins / Q000235:genetics; D015551:Autoimmunity; D002352:Carrier Proteins / Q000235:genetics; D009154:Mutation; D059365:Nonsense Mediated mRNA Decay; D051479:Plant Infertility / Q000235:genetics; D020365:RNA Helicases / Q000235:genetics; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; C533783:SMG7 protein, Arabidopsis; C513125:UPF1 protein, Arabidopsis; D020365:RNA Helicases