EXECUTER1- and EXECUTER2-dependent transfer of stress-related signals from the plastid to the nucleus of Arabidopsis thaliana.
Shortly after the release of singlet oxygen ((1)O2), drastic changes in nuclear gene expression occur in the conditional flu mutant of Arabidopsis that reveal a rapid transfer of signals from the plastid to the nucleus. In contrast to retrograde control of nuclear gene expression by plastid signals described earlier, the primary effect of (1)O2 generation in the flu mutant is not the control of chloroplast biogenesis but the activation of a broad range of signaling pathways known to be involved in biotic and abiotic stress responses. This activity of a plastid-derived signal suggests a new function of the chloroplast, namely that of a sensor of environmental changes that activates a broad range of stress responses. Inactivation of the plastid protein EXECUTER1 attenuates the extent of (1)O2-induced up-regulation of nuclear gene expression, but it does not fully eliminate these changes. A second related nuclear-encoded protein, dubbed EXECUTER2, has been identified that is also implicated with the signaling of (1)O2-dependent nuclear gene expression changes. Like EXECUTER1, EXECUTER2 is confined to the plastid. Inactivation of both EXECUTER proteins in the ex1/ex2/flu triple mutant is sufficient to suppress the up-regulation of almost all (1)O2-responsive genes. Retrograde control of (1)O2-responsive genes requires the concerted action of both EXECUTER proteins within the plastid compartment.
Lee
Keun Pyo
KP
Institute of Plant Sciences, Plant Genetics, Swiss Federal Institute of Technology (ETH), CH-8092 Zurich, Switzerland.
Kim
Chanhong
C
Landgraf
Frank
F
Apel
Klaus
K
D000483:Alleles; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006720:Homozygote; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress; D018087:Plastids / Q000235:genetics / Q000378:metabolism*; D011521:Protochlorophyllide / Q000032:analysis / Q000302:isolation & purification; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D026082:Singlet Oxygen / Q000378:metabolism
D029681:Arabidopsis Proteins; D018076:DNA, Complementary; C521350:EXECUTER1 protein, Arabidopsis; C521351:EXECUTER2 protein, Arabidopsis; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D026082:Singlet Oxygen; D011521:Protochlorophyllide