Project description:A deep-sequencing approach was pursued utilizing 454 and Illumina sequencing methods to discover new genes involved in xyloglucan biosynthesis. cDNA sequences were generated from developing nasturtium (Tropaeolum majus) seeds, which produce large amounts of non-fucosylated xyloglucan as a seed storage polymer. In addition to known xyloglucan biosynthetic genes, a previously uncharacterized putative xyloglucan galactosyltransferase was identified. Analysis of an Arabidopsis thaliana mutant line defective in the corresponding ortholog (AT5G62220) revealed that this gene shows no redundancy with the previously characterized xyloglucan galactosyltransferase, MUR3, but is required for galactosyl-substitution of xyloglucan at a different position. The gene was termed XLT2 for Xyloglucan L-side chain galactosylTransferase position 2. It represents an enzyme in the same subclade of glycosyltransferase family 47 as MUR3. A double mutant defective in both MUR3 (mur3.1) and XLT2 led to an Arabidopsis plant with xyloglucan that consists essentially of only xylosylated glucosyl units, with no further substitutions.
Project description:Nasturtium (Tropaeolum majus L.) contains high concentrations of benzylglcosinolate. We found that a hydrolysis product of benzyl glucosinolate-the benzyl isothiocyanate (BITC)-modulates the intracellular localization of the transcription factor Forkhead box O 1 (FOXO1). FoxO transcription factors can antagonize insulin effects and trigger a variety of cellular processes involved in tumor suppression, longevity, development and metabolism. The current study evaluated the ability of BITC-extracted as intact glucosinolate from nasturtium and hydrolyzed with myrosinase-to modulate i) the insulin-signaling pathway, ii) the intracellular localization of FOXO1 and, iii) the expression of proteins involved in gluconeogenesis, antioxidant response and detoxification. Stably transfected human osteosarcoma cells (U-2 OS) with constitutive expression of FOXO1 protein labeled with GFP (green fluorescent protein) were used to evaluate the effect of BITC on FOXO1. Human hepatoma HepG2 cell cultures were selected to evaluate the effect on gluconeogenic, antioxidant and detoxification genes and protein expression. BITC reduced the phosphorylation of protein kinase B (AKT/PKB) and FOXO1; promoted FOXO1 translocation from cytoplasm into the nucleus antagonizing the insulin effect; was able to down-regulate the gene and protein expression of gluconeogenic enzymes; and induced the gene expression of antioxidant and detoxification enzymes. Knockdown analyses with specific siRNAs showed that the expression of gluconeogenic genes was dependent on nuclear factor (erythroid derived)-like2 (NRF2) and independent of FOXO1, AKT and NAD-dependent deacetylase sirtuin-1 (SIRT1). The current study provides evidence that BITC might have a role in type 2 diabetes T2D by reducing hepatic glucose production and increasing antioxidant resistance.
Project description:Nasturtium (<i>Tropaeolum majus</i> L.), as a medicinal plant, has a high phenolic content in its leaves and flowers. It is often used in salads as a dietary vegetable. Attracting strong demand, it could be a good candidate crop for a plant factory with artificial lighting (PFAL) that can achieve the mass production of high-quality crops with high productivity by regulating environmental conditions such as light. In this study, two experiments were conducted to investigate the effects of continuous lighting (CL) and different daily light integrals (DLIs) under CL on the growth, secondary metabolites, and light use efficiency (LUE) of nasturtium, all of which are essential in the successful cultivation in PFALs. In Experiment 1, two lighting models, the same DLI of 17.3 mol m<sup>-2</sup> d<sup>-1</sup> but different light periods (24 and 16 h) with different light intensities (200 and 300 µmol m<sup>-2</sup> s<sup>-1</sup>, respectively), were applied to nasturtium. The results showed that leaf production, secondary metabolites, and LUE were higher under the 24-h CL treatment than under the 16-h non-CL treatment. In Experiment 2, three DLI levels (17.3, 25.9, and 34.6 mol m<sup>-2</sup> d<sup>-1</sup>) under the CL condition were applied. The results showed that the growth parameters were positively correlated with the DLI levels under CL. The lowest DLI had the highest LUE. We conclude that the mass production of nasturtium under CL in PFALs is feasible, and the yield increases as DLI increases from 17.3 to 34.6 mol m<sup>-2</sup> d<sup>-1</sup> under CL without causing physiological stress on plants.