Project description:Camalexin, an indolic secondary metabolite, is the magor phytoalexin produced by Arabidopsis thaliana. Camalexin biosynthesis is induced by abiotic stresses such as heavy metal treatment (e.g AgNO3). With the aim of identifying positive regulators of camalexin biosynthesis in Arabidopsis, we listed putative transcription factor genes strongly induced during the time course of AgNO3 treatment from a transcriptome analysis.
Project description:Background: Dendrobium officinale, an endangered Chinese herb, has extensive therapeutic effects and contains bioactive ingredients including a large number of polysaccharides and alkaloids, and minimal flavonoids. Firstly, this study attempts to obtain the protocorm-like bodies of this plant through tissue culture to produce the main secondary metabolites whose distribution in each organelle and protocorm like bodies is analyzed. Then, analysis of the correlation between comparative transcriptome sequence and the metabolite content in different organs enables the discovery of putative genes encoding enzymes involved in the biosynthesis of polysaccharides and alkaloids, and flavonoids. Results: The optimum condition for protocorm-like bodies (PLBs) induction and propagation of D. officinale is established. For protocorm induction, we use the seed as the explant, and the optimum medium formula for PLBs propagation is 1/2 MS + α-NAA 0.5 mg·L-1 +6-BA 1.0 mg·L-1 + 2, 4-D 1.5-2.0 mg·L-1 + potato juice 100 g·L-1. The distribution of polysaccharides, alkaloids and flavonoids in D. officinale organs was clarified. Stems, PLBs and leaves have the highest content of polysaccharides, alkaloids and flavonoids, respectively. PLBs replace organs to produce alkaloids in D. officinale, and naringenin was only produced in stem. Hot water extraction (HWE) method was found outperforming the ultrasound-assisted extraction (UAE) method for polysaccharides from D. officinale. A comparative transcriptome analysis of the protocorm-like bodies and leaves of D. officinale showed genes encoding enzymes involved in polysaccharides, alkaloids and flavonoids biosynthetic pathway were differentially expressed. Putative genes encoding enzymes involved in polysaccharides, alkaloids and flavonoids synthetic pathway were identified. Notably, genes encoding enzymes of strictosidine beta-glucosidase, geissoschizine synthase and vinorine synthase in alkaloids biosynthesis of D. officinale are first reported. Conclusions: Our works, especially the identification of candidate genes encoding enzymes involved in metabolites biosynthesis will help to explore and protect the endangered genetic resources and will also facilitate further analysis of the molecular mechanism of secondary metabolites’ biosynthesis in D. officinale.
Project description:GlnK is an important nitrogen sensor protein in Streptomyces coelicolor. Deletion of glnK results in a medium-dependent failure of aerial mycelium and spore formation and loss of antibiotic production. Thus, GlnK is not only a regulator of nitrogen metabolism but also of morphological differentiation and secondary metabolite production. Through a comparative transcriptomic approach between the S. coelicolor wild-type and a S. coelicolor glnK mutant strain, 142 genes were identified that are differentially regulated in both strains. Among these are genes of the ram and rag operon, which are involved in S. coelicolor morphogenesis, as well as, genes involved in gas vesicle biosynthesis and ectoine biosynthesis. Surprisingly, no relevant nitrogen genes were found to be differentially regulated, revealing that GlnK is not an important nitrogen sensor under the tested conditions.
Project description:GlnK is an important nitrogen sensor protein in Streptomyces coelicolor. Deletion of glnK results in a medium-dependent failure of aerial mycelium and spore formation and loss of antibiotic production. Thus, GlnK is not only a regulator of nitrogen metabolism but also of morphological differentiation and secondary metabolite production. Through a comparative transcriptomic approach between the S. coelicolor wild-type and a S. coelicolor glnK mutant strain, 142 genes were identified that are differentially regulated in both strains. Among these are genes of the ram and rag operon, which are involved in S. coelicolor morphogenesis, as well as, genes involved in gas vesicle biosynthesis and ectoine biosynthesis. Surprisingly, no relevant nitrogen genes were found to be differentially regulated, revealing that GlnK is not an important nitrogen sensor under the tested conditions. 16 samples, no replicates; four hour resolution from 21-33h; one our resolution from 33-40 h; two hour resolution 40-50h
Project description:Our previous studies have shown that exogenous ethylene (ETH) may induce plant adventitious root development in cucumber. In this study, transcriptome technique was used to explore the key genes in ETH-induced rooting. The results revealed that ETH regulated 1415 diferentially expressed genes (DEGs) during rooting, among which 687 DEGs were up-regulated and 728 DEGs were down-regulated. According to Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis, the critical pathways involved in ETH-induced adventitious root development were selected for further study, including carbon metabolism [starch and sucrose metabolism, glycolysis / gluconeogenesis, citrate cycle (TCA cycle), oxidative phosphorylation, fatty acid biosynthesis and fatty acid degradation], secondary metabolite biosynthesis (phenylalanine metabolism and flavonoid biosynthesis) and plant hormone signal transduction. In carbon metabolism, ETH reduced t the expression of CsHK2, CsPK2 and CsCYP86A1, whereas enhanced the expression of CsBAM1 and CsBAM3. Moreover, ETH negatively regulated the transcript level of CsPAL and CsF3’M and positively mediated that of CsPAO in secondary metabolite biosynthesis pathway. Additionally, ETH could induce adventitious rooting by negatively regulating auxin and ETH signal transduction-related genes (CsLAX5, CsGH3.17, CsSUAR50 and CsERS) and positively regulating ABA and BR signaling transduction-related genes (CsPYL1, CsPYL5, CsPYL8, CsBAK1 and CsXTH3) . Furthermore, the results of real-time PCR about the mRNA levels of these genes were consistent with transcriptome results. Therefore, ETH may induce adventitious root development by regulating carbon metabolism-related genes, secondary metabolite biosynthesis-related genes and plant hormone signal transduction-related genes.
Project description:To identify the putative genes involved in theacrine biosynthesis in tea plant, we carried out comparative transcriptome analysis of Kucha (K6 and K11) and conventional varieties (YH 9 and QX 1).