Progress in plant metabolic engineering

Over the past few years, there has been a growing realization that metabolic pathways must be studied in the context of the whole cell rather than at the single pathway level, and that even the simplest modifications can send ripples throughout the entire system. Attention has therefore shifted away from reductionist, single-gene engineering strategies and towards more complex approaches involving the simultaneous overexpression and/or suppression of multiple genes. The use of regulatory factors to control the abundance or activity of several enzymes is also becoming more widespread. In combination with emerging methods to model metabolic pathways, this should facilitate the enhanced production of natural products and the synthesis of novel materials in a predictable and useful manner.     

植物代谢工程的研究现状

植物代谢工程是一个很有发展前景的新兴学科。它可通过多种方法对植物的代谢流进行改造,如加速限制步骤的反应,改变分叉代谢途径的流向,构建代谢旁路,引入转录调节因子、信号因子、植物激素合成基因,扩展和构建新的代谢途径等方法进行。并取得了一些有意义的研究结果。     

植物维生素E代谢工程研究

维生素E是一种脂溶性维生素,仅在光合细菌和高等植物中合成,是人体中必不可少的一种营养物质,具有重要的生物学功能。维生素E合成代谢研究一直受到人们的关注,已通过生物信息学及转基因技术完成了维生素E合成代谢关键酶基因的分离及功能鉴定,近来研究重点转移到利用代谢工程方法提高植物维生素E含量与活性上来。综述了维生素E合成代谢途径及其代谢工程的研究现状,并对未来维生素E代谢工程研究提出了展望。     

Nuclear magnetic resonance and plant metabolic engineering.

Nuclear magnetic resonance (NMR) can be used to measure metabolite levels and metabolic fluxes, to probe the intracellular environment, and to follow transport and energetics nondestructively. NMR methods are therefore powerful aids to understanding plant metabolism and physiology. Both spectroscopy and imaging can help overcome the unique challenges that plants present to the metabolic engineer by detecting, identifying, quantifying, and localizing novel metabolites in vivo and in extracts; revealing the composition and physical state of cell wall and other polymers; allowing the identification of active pathways; providing quantitative measures of metabolic flux; and testing hypotheses about the effects of engineered traits on plant physiological function. The aim of this review is to highlight recent studies in which NMR has contributed to metabolic engineering of plants and to illustrate the unique characteristics of NMR measurements that give it the potential to make greater contributions in the future.     

代谢工程在D-核糖生产中研究现状及应用前景

简要介绍了代谢工程的进展情况,并较为详细地从宿主的选择、加速限速反应、改变代谢流和生产过程的优化等方面论述了代谢工程在D-核糖基因工程菌构建方面的应用及其应用前景。     

New developments in engineering plant metabolic pathways

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氨基酸生产的代谢工程研究进展与发展趋势

氨基酸发酵是我国发酵工业的支柱产业,近年来,随着代谢工程的快速发展,氨基酸的代谢工程育种蓬勃发展。传统的正向代谢工程、基于组学分析与计算机模拟的反向代谢工程以及借鉴自然进化的进化代谢工程,都有越来越多的应用。在氨基酸的工业生产中涌现出了一系列具有高效生产、抗逆性强等优良性状的菌株。日益剧烈的市场竞争对菌株的选育提出了新的要求,如开发高附加值氨基酸品种、菌株代谢的动态调控、适应新工艺的要求等。文中介绍了氨基酸生产相关的代谢工程研究进展以及未来的发展趋势。     

Recent developments and future prospects of Vitreoscilla hemoglobin application in metabolic engineering

In hypoxic conditions, bacteria express a kind of hemoglobin, which is proposed to enhance respiration and energy metabolism by promoting oxygen delivery. Bacteria hemoglobin from Vitreoscilla stercoraria - Vitreoscilla hemoglobin (VHb), when expressed in various hosts in oxygen-limited conditions, has been shown to improve growth, protein secretion, metabolite productivity and stress resistance of hosts, thus rendering the protein promising in metabolic engineering, especially in plant metabolism optimization. In this review, many well-studies areas are presented to illustrate the potential of VHb application in biotechnology industry, to discuss the cellular mechanisms of VHb function and to show the wide variety of approaches taken within the field.     

Integrating genomics and metabolomics for engineering plant metabolic pathways

Plant metabolites are characterized by an enormous chemical diversity, every plant having its own complex set of metabolites. This variety poses analytical challenges, both for profiling multiple metabolites in parallel and for the quantitative analysis of selected metabolites. We are only just starting to understand the roles of these metabolites, many of them being involved in adaptations to specific ecological niches and some finding beneficial use (e.g. as pharmaceuticals). Spectacular advances in plant metabolomics offer new possibilities, together with the aid of systems biology, to explore the extraordinary complexity of the plant biochemical capacity. State-of-the art genomics tools can be combined with metabolic profiling to identify key genes that could be engineered for the production of improved crop plants.     

The interface between plant metabolic engineering and human health

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Highlights► People should increase their consumption of fruit and vegetables to reduce their risk of chronic diseases. ► Despite many campaigns uptake of fruit and vegetable consumption has been limited. ► Metabolic engineering can improve understanding of the roles of dietary phytonutrients. ► Data from nutritional studies of model foods can set targets for crop improvements. ► Nutritionally enhanced fruit and vegetables, developed through breeding or metabolic engineering, could contribute to health.     

Transcriptome data modeling for targeted plant metabolic engineering

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Highlights► Network analysis is essential for data mining of omics-based large-scale data sets. ► Gene coexpression analysis is useful for prediction of gene function. ► Comparative network analysis can reveal common and unique plant metabolic pathways. ► Novel genome editing tools facilitate rational metabolic engineering.     

The challenges of cellular compartmentalization in plant metabolic engineering

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Highlights► Targeting enzymes to organelles with highest precursor pool affects product yield. ► Targeting of nonendogenous enzymes to organelles is a useful tool for engineering. ► Identification of transporters is central for effective metabolic engineering. ► Advances in metabolomics of isolated organelles will impact engineering strategies. ► Future plant metabolic engineering will include introduction of entire pathways.     

Retrospect and prospects of secondary agriculture and bioprocessing

Secondary agriculture plays a significant role in making a positive impact on the country’s economy. It has potential to increase the value of primary agriculture. It ensures better utilization of renewable agro-bioresources either through value addition or waste utilization. Nurseries, bio-fertilizers, bio-pesticides, compost, fruit-processed products, agro-tourism, weaving, flavours, and dyes are some of the avenues of secondary agriculture. By-products from agricultural crops like wheat and rice bran, corn gluten meal and germ, pulses meal and husk, and sugarcane bagasse, if processed appropriately for deriving industrial products could pave a way in getting better economic returns from agriculture rather using them as livestock feed. Among food crops, major post-harvest losses (30–40%) occurs in fruits and vegetables; their waste being rich in several bioactive compounds possess great potential to be added as a polyphenol rich and fibre source in food products or for the synthesis of food-grade industrial products like ethanol, citric acid and pectin etc. Wastes from floriculture industries can also be utilised for the production of several value-added products such as biofuels, bio-ethanol, compost, organic acids, pigments and dyes, incense sticks, handmade paper production, and sugar syrup. Around the world, 80% of population is dependent on traditional medicine for health care needs. The secondary metabolites from medicinal plants possess pharmaceutical properties and advancement in extraction techniques can lead to novel range of herbal products of high economic value. The market potential of agro-produce seems to be naïve but opportunistic in near future. The advancement in technologies, equipments, and processes would enable enhanced secondary agriculture practices giving range of materials of better quality, yield, nutrition, and convenience. Hence, the potential of secondary agriculture and bioprocessing could be strong boost to the economy, societal status and environmental protection. In this article we have made an effort to understand the secondary agriculture, its potential to uplift the economy and strategies for value addition in different agricultural domains such as horticulture, floriculture and medicinal plants.     

Transformation techniques for metabolic engineering of diatoms and haptophytes: current state and prospects

Applied Microbiology and Biotechnology - Diatoms and haptophytes represent a key segment of the dominant phytoplankton communities that frequently form massive blooms in the photic zone of the...     

Production and metabolic engineering of bioactive substances in plant hairy root culture

In the past three decades, hairy roots research for the production of valuable biological active substances has received a lot of attention. The addition of knowledge to enhance the yields of desired substances and the development of novel tools for biomass engineering offer new possibilities for large-scale cultivation of the plant hairy root. Hairy roots can also produce recombinant proteins through the transfer of Agrobacterium T-DNA into the plant genome, and thereby hold immense potential for the pharmaceutical industry. This review highlights some of the significant progress made in the past few years and outlines future prospects for exploiting the potential utility of hairy root cultures as “chemical factories” for producing bioactive substances.     

L-valine production in Corynebacterium glutamicum based on systematic metabolic engineering: progress and prospects

L-valine is an essential branched-chain amino acid that cannot be synthesized by the human body and has a wide range of applications in food, medicine and feed. Market demand has stimulated people’s interest in the industrial production of L-valine. At present, the mutagenized or engineered Corynebacterium glutamicum is an effective microbial cell factory for producing L-valine. Because the biosynthetic pathway and metabolic network of L-valine are intricate and strictly regulated by a variety of key enzymes and genes, highly targeted metabolic engineering can no longer meet the demand for efficient biosynthesis of L-valine. In recent years, the development of omics technology has promoted the upgrading of traditional metabolic engineering to systematic metabolic engineering. This whole-cell-scale transformation strategy has become a productive method for developing L-valine producing strains. This review provides an overview of the biosynthesis and regulation mechanism of L-valine, and summarizes the current metabolic engineering techniques and strategies for constructing L-valine high-producing strains. Finally, the opinion of constructing a cell factory for efficiently biosynthesizing L-valine was proposed.

     

Plastid biotechnology: prospects for herbicide and insect resistance, metabolic engineering and molecular farming

Transgene expression from the chloroplast (plastid) genome offers several attractions to plant biotechnologists, including high-level accumulation of foreign proteins, transgene stacking in operons and a lack of epigenetic interference with the stability of transgene expression. In addition, the technology provides an environmentally benign method of plant genetic engineering, because plastids and their genetic information are maternally inherited in most crops and thus are largely excluded from pollen transmission. During the past few years, researchers in both the public and private sectors have begun to explore possible areas of application of plastid transformation in plant biotechnology as a viable alternative to conventional nuclear transgenic technologies. Recent proof-of-concept studies highlight the potential of plastid genome engineering for the expression of resistance traits, the production of biopharmaceuticals and metabolic pathway engineering in plants.     

Recent progress in the metabolic engineering of alkaloids in plant systems

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Highlights► Recent metabolic engineering efforts for plant alkaloids. ► Characterizing, reconfiguring and fine-tuning metabolic ‘parts’ improves titers. ► Additional strategies are necessary to produce ‘unnatural’ natural products.