Project description:Detoxification of chlorophyll during leaf senescence in higher plants is a complex and tightly regulated process. It aims at opening the chlorophyll porphyrin ring to produce non-photoreactive degradation products, termed phyllobilins, which are stored in the vacuole. Here we are describing the influence on the transcriptome of dark-induced senescing leaf of the removal of three key enzymes of the PAO/phyllobilin pathway (namely: PAO, PPH and NYE/SGR).
Project description:To identify the regulatory steps that control chlorophyll accumulation, we compared gene expression in petals and leaves of chrysanthemum cultivars with different chlorophyll levels. Microarray analyses showed that the expression levels of chlorophyll biosynthesis genes encoding glutamyl-tRNA reductase, Mg-protoporphyrin IX chelatase, Mg-protoporphyrin IX monomethylester cyclase, and protochlorophyllorophyllide oxidoreductase were well associated with chlorophyll content: their expression levels were lower in white petals than in green petals, and were highest in leaves. Among chlorophyll catabolic genes, expression of STAY-GREEN, encoding Mg-dechelatase, which is a key enzyme controlling chlorophyll degradation, was considerably higher in white and green petals than in leaves. We searched for transcription factor genes whose expression was well related to chlorophyll level in petals and leaves and found several such genes.
Project description:This SuperSeries is composed of the following subset Series: GSE36341: mRNA degradation in Mycobacterium tuberculosis under aerobic conditions GSE36342: mRNA degradation in Mycobacterium smegmatis under aerobic conditions GSE36343: mRNA degradation in Mycobacterium tuberculosis during cold and hypoxic stress GSE36344: mRNA degradation in Mycobacterium tuberculosis with DosR ectopically induced Refer to individual Series
Project description:Heterologous expression of a water soluble chlorophyll protein from Brassica oleracea var. gemmifera in the phototrophic purple bacterium Rhodobacter sphaeroides was verified by bottom-up proteomic analysis.
Project description:The marine obligate hydrocarbonoclastic bacterium Thalassolituus oleivorans MIL-1 metabolises a broad range of aliphatic hydrocarbons almost exclusively as carbon and energy sources. We used LC-MS/MS shotgun proteomics to identify proteins involved in aerobic alkane degradation during growth on medium- (n-C14) or long-chain (n-C28) alkanes.
Project description:Chlorophyll (Chl) degradation is an important process during leaf senescence, bud breaking and fruit ripening. Chlorophyll catabolic pathway has been intensively studied and nearly all the enzymes involved in the pathway are characterized. However, regulatory mechanism of the pathway is largely unknown at the molecular level. In this study, we performed a yeast one-hybrid screening using a library composed only of transcription factor cDNAs to search for factors controlling expression of the chlorophyll catabolic genes. We identified a common regulator, ANAC046, that directly binds to the promoter regions of NON-YELLOW COLORING 1, STAY-GREEN 1 (SGR1), SGR2, and pheophorbide a oxygenase. Transgenic plants overexpressing ANAC046 exhibited an early senescence phenotype with lower chlorophyll content as compared with the wild-type plants, while loss-of-function mutants exhibited a delayed senescence phenotype with higher chlorophyll content. Microarray analysis of ANAC046 showed that not only chlorophyll catabolic genes but also senescence-associated genes were positively regulated by ANAC046. Here, we demonstrate that ANAC046 is a novel positive regulator of Arabidopsis leaf senescence and exerts its effect through controlling the expressions of Chl catabolic genes and senescence-associated genes.
Project description:Chlorophyll (Chl) degradation is an important process during leaf senescence, bud breaking and fruit ripening. Chlorophyll catabolic pathway has been intensively studied and nearly all the enzymes involved in the pathway are characterized. However, regulatory mechanism of the pathway is largely unknown at the molecular level. In this study, we performed a yeast one-hybrid screening using a library composed only of transcription factor cDNAs to search for factors controlling expression of the chlorophyll catabolic genes. We identified a common regulator, ANAC046, that directly binds to the promoter regions of NON-YELLOW COLORING 1, STAY-GREEN 1 (SGR1), SGR2, and pheophorbide a oxygenase. Transgenic plants overexpressing ANAC046 exhibited an early senescence phenotype with lower chlorophyll content as compared with the wild-type plants, while loss-of-function mutants exhibited a delayed senescence phenotype with higher chlorophyll content. Microarray analysis of ANAC046 showed that not only chlorophyll catabolic genes but also senescence-associated genes were positively regulated by ANAC046. Here, we demonstrate that ANAC046 is a novel positive regulator of Arabidopsis leaf senescence and exerts its effect through controlling the expressions of Chl catabolic genes and senescence-associated genes. Transcriptomes of leaf of ANAC046-overexpression plant (50 days after seed sawing), seedling of ANAC046-SRDX-overexpression plant (5 days after dark treatment), and seedling of ANAC046-knockout plant (5 days after dark treatment) were measured together with their respective wild-type controls.
Project description:Side chain modifications of phyllobilins are not essential for chlorophyll degradation during dark-induced senescence in Arabidopsis
Project description:Degradation of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene by anaerobic microorganisms is poorly understood. Strain NaphS2, an anaerobic sulfate reducing marine delta-proteobacterium is capable of using naphthalene and the aromatic compound benzoate, as well as pyruvate, as an electron donors in the presence of sulfate. In order to identify genes involved in the naphthalene degradation pathway, we compared gene expression in NaphS2 during growth on benzoate vs. pyruvate, naphthalene vs. pyruvate, and naphthalene vs benzoate.
