ABSTRACT
Obesity is the most prevalent disease in the world which poses a serious risk for various chronic diseases. However, currently there are not any therapeutic agents that reduce body weight without causing serious side effects. In order to prevent and/or treat obesity and related diseases through a nutraceutical approach, we created a resveratrol-enriched transgenic rice accumulating 1.4 µg/g of resveratrol in its grain, DJ-526. Feeding of mice with the resveratrol-enriched rice DJ-526 showed excellent anti-obesity effect with reduction of body weights and abdominal fat volumes compared to the control by 20.0% and 31.3%, respectively. Also, the consumption of the resveratrol-enriched rice DJ526 significantly improved the blood lipid profiles and glucose levels in the animal experiments. Our resveratrol-enriched rice DJ-526 rice could provide both safe and convenient way for people with obesity and related diseases without major change of lifestyle or unwanted side effects from medication.
Subject(s)
Anti-Obesity Agents/therapeutic use , Obesity/diet therapy , Oryza/chemistry , Plants, Genetically Modified , Stilbenes/therapeutic use , Abdominal Fat , Animals , Blood Glucose/metabolism , Body Weight , Chromatography, High Pressure Liquid , Female , Lipids/blood , Mice , Mice, Inbred C57BL , ResveratrolABSTRACT
We examined to determine whether senescence-induced tryptophan levels are positively associated with levels of glutamine synthetase (GS1), the initial enzyme in tryptophan biosynthesis. We generated transgenic rice plants in which GS1 was suppressed by RNA interference technology. The transgenic line showed a dramatic decrease in GS1 protein and glutamine content, but the levels of tryptophan and mRNA of the key tryptophan biosynthetic genes upon senescence were comparable to those of the wild type.
Subject(s)
Aging/physiology , Glutamate-Ammonia Ligase , Tryptophan/biosynthesis , Cytosol/enzymology , Glutamine/analysis , Oryza/genetics , Plants, Genetically Modified , RNA Interference , RNA, Messenger/analysis , Tryptophan/analysisABSTRACT
Coordination of multiple transgenes is essential for metabolic engineering of biosynthetic pathways. Here, we report the utilization of two bicistronic systems involving the 2A sequence from the foot-and-mouth disease virus and the internal ribosome entry site (IRES) sequence from the crucifer-infecting tobamovirus to the biosynthesis of carotenoids in rice endosperm. Two carotenoid biosynthetic genes, phytoene synthase (Psy) from Capsicum and carotene desaturase (CrtI) from Pantoea, were linked via either the synthetic 2A sequence that was optimized for rice codons or the IRES sequence under control of the rice globulin promoter, generating PAC (Psy-2A-CrtI) and PIC (Psy-IRES-CrtI) constructs, respectively. The transgenic endosperm of PAC rice had a more intense golden color than did PIC rice, demonstrating that 2A was more efficient than IRES in coordinating gene expression. The 2A and IRES constructs were equally effective in driving transgene transcription. However, immunoblot analysis of CRTI, a protein encoded by the downstream open reading frame of the bicistronic constructs, revealed that 2A was ninefold more effective than IRES in driving translation. The PAC endosperms accumulated an average of 1.3 µg/g of total carotenoids, which was ninefold higher than was observed for PIC endosperms. In particular, accumulation of ß-carotene was much higher in PAC endosperms than in PIC endosperms. Collectively, these results demonstrate that both 2A and IRES systems can coordinate the expression of two biosynthetic genes, with the 2A system exhibiting greater efficiency. Thus, the 2A expression system described herein is an effective new tool for multigene stacking in crop biotechnology.
Subject(s)
Biotechnology/methods , Carotenoids/biosynthesis , Endosperm/metabolism , Oryza/metabolism , Plants, Genetically Modified/metabolism , Alkyl and Aryl Transferases/genetics , Endosperm/genetics , Genetic Engineering/methods , Geranylgeranyl-Diphosphate Geranylgeranyltransferase , Oryza/genetics , Oxidoreductases/genetics , Plant Proteins/genetics , Plants, Genetically Modified/geneticsABSTRACT
To increase insect resistance in transgenic rice plants, a synthetic truncated cry1Ac gene was linked to the rice rbcS promoter and its transit peptide sequence (tp) for chloroplast-targeted expression. Several transgenic lines were generated by the Agrobacterium-mediated transformation method and the expression levels of the transgene were compared with untargeted expression. Use of the rbcS-tp sequence increased the cry1Ac transcript and protein levels by 25- and 100-fold, respectively, with the accumulated protein in chloroplasts comprising up to 2% of the total soluble proteins. The high level of cry1Ac expression resulted in high levels of plant resistance to three common rice pests, rice leaf folder, rice green caterpillar, and rice skipper, as evidenced by insect feeding assays. Transgenic plants were also evaluated for resistance to natural infestations by rice leaf folder under field conditions. Throughout the entire period of plant growth, the transgenic plants showed no symptoms of damage, whereas nontransgenic control plants were severely damaged by rice leaf folders. Our results demonstrate that the targeting of cry1Ac protein to the chloroplast using the rbcS:tp system confers a high level of plant protection to insects, thus providing an alternative strategy for crop insect management.
