Project description:Plastid gene expression (PGE) acts as a signal that regulates the expression of photosynthesis-associated nuclear genes (PhANGs) via GENOMES UNCOUPLED1 (GUN1)-dependent retrograde signaling. We recently isolated Arabidopsis sugar-inducible cotyledon yellow-192 (sicy-192), a gain-of-function mutant of plastidic invertase (INV-E), and showed that following the treatment of this mutant with sucrose, the expression of PhANGs decreased while that of nitrate reductase 1 (NIA1) increased. Plastid-encoded RNA polymerase (PEP)-dependent PGE was markedly suppressed in the sicy-192 mutant by the sucrose treatment. A double mutant of sicy-192 and gun1-101, a null mutant of GUN1, revealed that metabolic perturbation in the sucrose-treated sicy-192 mutant was, at least in part, dependent on GUN1. To confirm whether there is a relationship between plastid sugar metabolism and nuclear gene expression, we performed a microarray analysis using Suc-treated 3 genotypes consisting of wild-type, sicy-192, and sicy-192 gun1-101 plants.
Project description:Plastid gene expression (PGE) acts as a signal that regulates the expression of photosynthesis-associated nuclear genes (PhANGs) via GENOMES UNCOUPLED1 (GUN1)-dependent retrograde signaling. We recently isolated Arabidopsis sugar-inducible cotyledon yellow-192 (sicy-192), a gain-of-function mutant of plastidic invertase (INV-E), and showed that following the treatment of this mutant with sucrose, the expression of PhANGs decreased while that of nitrate reductase 1 (NIA1) increased. Plastid-encoded RNA polymerase (PEP)-dependent PGE was markedly suppressed in the sicy-192 mutant by the sucrose treatment. A double mutant of sicy-192 and gun1-101, a null mutant of GUN1, revealed that metabolic perturbation in the sucrose-treated sicy-192 mutant was, at least in part, dependent on GUN1. To confirm whether there is a relationship between plastid sugar metabolism and nuclear gene expression, we performed a microarray analysis using Suc-treated 3 genotypes consisting of wild-type, sicy-192, and sicy-192 gun1-101 plants. Wild-type, sicy-192, and sicy-192 gun1-101 plants were grown on MS medium containing 100 mM sucrose in a growth chamber kept at 25°C during 16 h of light (100 µmol/m2/s) and at 22°C during 8 h of darkness for 4 days. At 4 days of age, cotyledons were collected as samples for microarray analysis.
Project description:GUN1 proteins controls protein homeostasis in chloroplast development in cotyledons of the model plant Arabidopsis thaliana, via coordination of nuclear encoded polymerase (NEP)-dependent chloroplast genes expression with plastid encoded polymerase (PEP)-dependent chloroplast genes expression. Lack of GUN1 leads to development of abnormal plastids and, consequently, accumulation of nuclear-encoded chloroplast-targeted (NECT) proteins which in many cases have been found still in their precursor form. Data dependent acquisition (DDA) mass spectrometry analysis of cotyledons soluble fractions, as well as targeted proteomics analysis of specific FtsH protease forms recognized by FtsH antibodies in western blotting, have been performed to identify peptides from the chloroplast transit peptide (cTP) of NECT in cotyledons extracts of wild type and GUN1 knocked-out mutant plants. The aim was to compare the number of cTPs found in 6 days after sowing (DAS) seedlings grown on plates with or without the inhibitor of plastid translation lincomycin.
Project description:Arabidopsis thaliana mutant sr45-1 has an altered flower shape. sr45 is a splicing regulator. In this study, we examined the proteins from inflorescence of sr45-1 mutant plants and wild-type. Wild type TMT labels: 126, 128, 130. sr45-1 TMT labels: 127, 129, 131.
Project description:How bacteria from the microbiota modulate the physiology of its host is an important question to address. Previous work revealed that the metabolic status of Arabidopsis thaliana was crucial for the specific recruitment of Streptomycetaceae into the microbiota. Here, the Arabidopsis-Actinacidiphila interaction was further depicted by inoculating axenic Arabidopsis with Actinacidiphila cocklensis DSM 42063 or Actinacidiphila bryophytorum DSM 42138(previously named Streptomyces cocklensis and Streptomyces bryophytorum). We demonstrated that these two bacteria colonize A. thaliana wild-type plants, but their colonization efficiency was reduced in a chs5 mutant with defect in isoprenoid, phenylpropanoids and lipids synthesis. We observed that those bacteria affect the growth of the chs5 mutant but not of the wild-type plants. Using a mass spectrometry-based proteomic approach, we showed a modulation of the Arabidopsis proteome and in particular its components involved in photosynthesis or phytohormone homeostasis or perception by A. cocklensis and A. bryophytorum. This study unveils specific aspects of the Actinacidiphila-Arabidopsis interaction, which implies molecular processes impaired in the chs5 mutant and otherwise at play in the wild-type. More generally, this study highlights complex and distinct molecular interactions between Arabidopsis thaliana and bacteria belonging to the Actinacidiphila genus.