title: Mitochondrial AtPAM16 is required for plant survival and the negative regulation of plant immunity.
abstract: Proteins containing nucleotide-binding and leucine-rich repeat domains (NB-LRRs) serve as immune receptors in plants and animals. Negative regulation of immunity mediated by NB-LRR proteins is crucial, as their overactivation often leads to autoimmunity. Here we describe a new mutant, snc1-enhancing (muse) forward genetic screen, targeting unknown negative regulators of NB-LRR-mediated resistance in Arabidopsis. From the screen, we identify MUSE5, which is renamed as AtPAM16 because it encodes the ortholog of yeast PAM16, part of the mitochondrial inner membrane protein import motor. Consistently, AtPAM16-GFP localizes to the mitochondrial inner membrane. AtPAM16L is a paralog of AtPAM16. Double mutant Atpam16-1 Atpam16l is lethal, indicating that AtPAM16 function is essential. Single mutant Atpam16 plants exhibit a smaller size and enhanced resistance against virulent pathogens. They also display elevated reactive oxygen species (ROS) accumulation. Therefore, AtPAM16 seems to be involved in importing a negative regulator of plant immunity into mitochondria, thus protecting plants from over-accumulation of ROS and preventing autoimmunity.
authors.affiliation: 1] Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada [2] Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada [3].
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.forename: Xuejin
authors.initials: X
authors.lastname: Chen
authors.forename: Yanan
authors.initials: Y
authors.lastname: Liu
authors.forename: Charlotte
authors.initials: C
authors.lastname: Roth
authors.forename: Charles
authors.initials: C
authors.lastname: Copeland
authors.forename: Heather E
authors.initials: HE
authors.lastname: McFarlane
authors.forename: Shuai
authors.initials: S
authors.lastname: Huang
authors.forename: Volker
authors.initials: V
authors.lastname: Lipka
authors.forename: Marcel
authors.initials: M
authors.lastname: Wiermer
authors.forename: Xin
authors.initials: X
authors.lastname: Li
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000276:immunology*; D018506:Gene Expression Regulation, Plant / Q000276:immunology*; D049452:Green Fluorescent Proteins; D057166:High-Throughput Screening Assays; D008928:Mitochondria / Q000235:genetics / Q000276:immunology*; D033681:Mitochondrial Membrane Transport Proteins / Q000145:classification / Q000235:genetics / Q000276:immunology*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D009154:Mutation; D009868:Oomycetes / Q000276:immunology; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D057865:Plant Immunity / Q000235:genetics*; D017382:Reactive Oxygen Species / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; C000588830:PAM16 protein, Arabidopsis thaliana; C484526:Pam16 protein, S cerevisiae; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins