Autoimmunity in Arabidopsis acd11 Is Mediated by Epigenetic Regulation of an Immune Receptor

PLoS Pathogens

Morten Petersen¹  Peter Brodersen¹  Kristoffer Palma¹  Daniel Hofius¹  John Mundy¹  Stephan Thorgrimsen¹  Frederikke Gro Malinovsky¹  Berthe Katrine Fiil¹  H. Bjørn Nielsen² 

[1] Department of Biology, University of Copenhagen, Copenhagen, Denmark;Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark

关键词: Cell death;    Chromatin;    Arabidopsis thaliana;    Histones;    Genetic loci;    Point mutation;    Methylation;    Plant pathogens;   

DOI  :  10.1371/journal.ppat.1001137

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Certain pathogens deliver effectors into plant cells to modify host protein targets and thereby suppress immunity. These target modifications can be detected by intracellular immune receptors, or Resistance (R) proteins, that trigger strong immune responses including localized host cell death. The accelerated cell death 11 (acd11) “lesion mimic” mutant of Arabidopsis thaliana exhibits autoimmune phenotypes such as constitutive defense responses and cell death without pathogen perception. ACD11 encodes a putative sphingosine transfer protein, but its precise role during these processes is unknown. In a screen for lazarus (laz) mutants that suppress acd11 death we identified two genes, LAZ2 and LAZ5. LAZ2 encodes the histone lysine methyltransferase SDG8, previously shown to epigenetically regulate flowering time via modification of histone 3 (H3). LAZ5 encodes an RPS4-like R-protein, defined by several dominant negative alleles. Microarray and chromatin immunoprecipitation analyses showed that LAZ2/SDG8 is required for LAZ5 expression and H3 lysine 36 trimethylation at LAZ5 chromatin to maintain a transcriptionally active state. We hypothesize that LAZ5 triggers cell death in the absence of ACD11, and that cell death in other lesion mimic mutants may also be caused by inappropriate activation of R genes. Moreover, SDG8 is required for basal and R protein-mediated pathogen resistance in Arabidopsis, revealing the importance of chromatin remodeling as a key process in plant innate immunity.

【 授权许可】

CC BY