title: The GHKL ATPase MORC1 Modulates Species-Specific Plant Immunity in Solanaceae.
abstract: The microrchidia (MORC) proteins, a subset of the GHKL ATPase superfamily, were recently described as components involved in transcriptional gene silencing and plant immunity in Arabidopsis. To assess the role of MORC1 during resistance to Phytophthora infestans in solanaceous species, we altered the expression of the corresponding MORC1 homologs in potato, tomato, and Nicotiana benthamiana. Basal resistance to P. infestans was compromised in StMORC1-silenced potato and enhanced in overexpressing lines, indicating that StMORC1 positively affects immunity. By contrast, silencing SlMORC1 expression in tomato or NbMORC1 expression in N. benthamiana enhanced basal resistance to this oomycete pathogen. In addition, silencing SlMORC1 further enhanced resistance conferred by two resistance genes in tomato. Transient expression of StMORC1 in N. benthamiana accelerated cell death induced by infestin1 (INF1), whereas SlMORC1 or NbMORC1 suppressed it. Domain-swapping and mutational analyses indicated that the C-terminal region dictates the species-specific effects of the solanaceous MORC1 proteins on INF1-induced cell death. This C-terminal region also was required for homodimerization and phosphorylation of recombinant StMORC1 and SlMORC1, and its transient expression induced spontaneous cell death in N. benthamiana. Thus, this C-terminal region likely plays important roles in both determining and modulating the biological activity of MORC1 proteins.
authors.affiliation: 1 Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A.;|2 Department of Plant Pathology and Microbiology, University of California Riverside, Riverside 92521, U.S.A.;
authors.forename: Patricia
authors.initials: P
authors.lastname: Manosalva
authors.affiliation: 1 Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A.;
authors.forename: Murli
authors.initials: M
authors.lastname: Manohar
authors.affiliation: 3 Research Centre for BioSystems, Land Use, and Nutrition, Justus Liebig University, Giessen D-35392, Germany; and.
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Kogel
authors.affiliation: 4 Department of Biology, Texas State University, San Marcos 78666, U.S.A.
authors.forename: Hong-Gu
authors.initials: HG
authors.lastname: Kang
authors.affiliation: 1 Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, U.S.A.;
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Klessig
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D054884:Host-Pathogen Interactions / Q000276:immunology*; D018551:Solanum lycopersicum / Q000276:immunology / Q000382:microbiology; D010766:Phosphorylation; D010802:Phylogeny; D055750:Phytophthora infestans / Q000472:pathogenicity; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D057865:Plant Immunity; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012717:Sesquiterpenes / Q000494:pharmacology; D019657:Solanaceae / Q000276:immunology* / Q000382:microbiology*; D011198:Solanum tuberosum / Q000276:immunology / Q000382:microbiology; D014026:Nicotiana / Q000276:immunology / Q000382:microbiology
chemical_list: D010940:Plant Proteins; D012717:Sesquiterpenes; C528839:radicol; D000251:Adenosine Triphosphatases