Project description:Phalaenopsis aprodite subsp. formosana is one of the most important species for Phalaenopsis breeding. A mutant line with variegated leaf is found in this species. The green leaves bear unstable yellow sectors. In order to investigate the molecular mechanism of the variegated mutant line, we sequenced the transcriptome of variegated mutant by Illumina's Solexa sequencing technology. The sequence analysis results showed 22,598 unigenes by de novo assembly method, and the average unigene length was 1,286 bp. The bioinformatics tools were used to screen the differential expression between green and yellow sectors of leaves. There were 389 differentially expressed unigenes were identified. In addition, Gene ontology (GO) and KEGG pathway analyses revealed diverse biological functions and processes from differentially expressed genes. In transcriptome analysis, seven differential expression gene between the green and yellow sectors of leaves can be identified as CHLM, CRD1, POR, CLH, SGR, psbA and Lhcb6 by RNA deep sequencing. The expression of candidate genes was confirmed using semi-quantitative reverse transcription (RT) PCR and real-time RT PCR. The result showed that the significantly differential expression of CLH and SGR between green and yellow sectors was confirmed. It is suggested that the overexpressed SGR gene promotes the function of chlorophyllase, leading to the rapid degradation of chlorophyll in yellow sector. It causes the chlorophyll to not accumulate in the yellow sector, as a result, the variegated leaves are shown.
Project description:Chinese orchid is a symbol of elegance and purity in China. Among the Chinese orchids, the leaf color variation of Cymbidium sinense (C. sinense) is the most abundant. The variation of leaf color makes the C. sinense more diversified and more valuable, however, its formation mechanism still needs more extensive exploration. Using TMT and LC-MS/MS analysis, the proteome and phos-phoproteome of C. sinense leaf variegation mutant were studied.
Project description:The yellow variegated2 (var2) mutant in Arabidopsis thaliana has been studied as a typical leaf-variegated mutant whose defect results from the lack of FtsH2 metalloprotease in chloroplasts. The var2 green sectors suffer from photooxidative stress and accumulate high levels of reactive oxygen species (ROS) because of compromised Photosystem II repair. This study investigated and compared microarray-based expression profiles of green and white sectors of var2 leaves. Results suggest that ROS that accumulate in chloroplasts of var2 green sectors do not cause much significant change of the transcriptional profile related to ROS signaling and scavenging. In contrast, transcriptome in white sectors apparently differs from those in green sectors and wild type. Numerous genes related to photosynthesis and chloroplast functions were repressed in white sectors. Furthermore, many genes related to oxidative stress were up-regulated. Among them, we specifically examined ROS scavenging genes, such as Cu/Zn superoxide dismutase 2 (CSD2), that were apparently up-regulated in white but not in green sectors. Up-regulation of CSD2 appears to be partly attributable to the lack of a microRNA (miR398) in white sectors. Together, we concluded that white sectors exhibit response to oxidative and other stresses, including CSD2 up-regulation, which might be commonly found in tissues with abnormal chloroplast differentiation.
Project description:The yellow variegated2 (var2) mutant in Arabidopsis thaliana has been studied as a typical leaf-variegated mutant whose defect results from the lack of FtsH2 metalloprotease in chloroplasts. The var2 green sectors suffer from photooxidative stress and accumulate high levels of reactive oxygen species (ROS) because of compromised Photosystem II repair. This study investigated and compared microarray-based expression profiles of green and white sectors of var2 leaves. Results suggest that ROS that accumulate in chloroplasts of var2 green sectors do not cause much significant change of the transcriptional profile related to ROS signaling and scavenging. In contrast, transcriptome in white sectors apparently differs from those in green sectors and wild type. Numerous genes related to photosynthesis and chloroplast functions were repressed in white sectors. Furthermore, many genes related to oxidative stress were up-regulated. Among them, we specifically examined ROS scavenging genes, such as Cu/Zn superoxide dismutase 2 (CSD2), that were apparently up-regulated in white but not in green sectors. Up-regulation of CSD2 appears to be partly attributable to the lack of a microRNA (miR398) in white sectors. Together, we concluded that white sectors exhibit response to oxidative and other stresses, including CSD2 up-regulation, which might be commonly found in tissues with abnormal chloroplast differentiation. Arabidopsis thaliana ecotype Columbia (Col), used as the wild-type, and var2-1 (var2) were grown in MS medium supplemented with Gamborgâ??s vitamins (Sigma-Aldrich). MS medium was supplemented with 1.5% (w/v) sucrose and 0.7% (w/v) agar. Plants were maintained under a 12 h light (70 μmolâ?¢m-2â?¢s-1)/12 h dark cycle at 22°C. Green and white sectors, surgically separated and collected from 4-week-old true leaves were subjected to total RNA extraction. We also extracted total RNA from Col. Three biological replicates were performed for each sample.
Project description:To unveil the role of posttranslational modification in the variegated phenotype, we conducted global quantitative phosphoproteomic analysis on different leaf color sectors of Maiyuanjinqiu and the corresponding of Catalpa fargesii using Ti4+-IMAC phosphopeptide enrichment. 3778 phosphorylated sites assigned to 1646 phosphoproteins were identified, and 3221 in 1434 proteins were quantified. Differential phosphoproteins (above 1.5 or below 1/1.5) in various leaf color sectors were selected for functional enrichment analyses. GO enrichment revealed that processes of photosynthesis, regulation of the generation of precursor metabolites, response to stress, homeostasis, amino acid metabolism, transport–related processes and most of the energy metabolisms might contribute to leaf color. KEGG pathway enrichment analysis was performed based on differential phosphoproteins (DPs) in different organelles. The result showed that most enriched pathways were located in the chloroplasts and cytosol. The phosphorylation levels of glycometabolism enzymes might greatly affect leaf variegation.
Project description:Monitor changes in the proteome of senescing leaves, using protein MS data obtained from the same leaf groups used for imaging. Arabidopsis thaliana mature leaves were grouped according to their chlorophyll content: Dark Green (DG), Green (G), Light Green (LG) and Yellow (Y), containing 100, 45, 25 and 6.5% chlorophyll relative to DG, respectivelyArabidopsis thaliana mature leaves were grouped according to their chlorophyll content: Dark Green (DG), Green (G), Light Green (LG) and Yellow (Y), containing 100, 45, 25 and 6.5% chlorophyll relative to DG, respectively
Project description:To explore the mechanisms governing the leaf color variations in Chinese orchids, we analyzed gene expression differences between a wild-type and an albino-type cultivar of Cymbidium longibracteatum