Using plants to remove or inactivate heavy metal pollutants from soils and surface waters provide a cheap and sustainable approach of Phytoremediation. However, field trials suggested that the efficiency of contaminant removal using natural hyperaccumulators is insufficient, due to that many of these species are slow growing and produce little shoot biomass. These factors severely constrain their potential for large-scale decontamination of polluted soils. Moreover, both the micronutrient and toxic metal content accumulated in crops determine the quality and safety of our food-chain. By a transgenic approach, the introduction of novel genes responsible for hyperaccumulating phenotype into high biomass plants and/or stable crops uptaking minerals as food is a promising strategy for the development of effective techniques of phytoremediation and improvement of nutritional value of stable food through a viable commercialization. Recently, the progress at molecular level for heavy metal uptaking, detoxification and hyperaccumulation in plants, and also the clarification of some functional genes in bacteria, yeasts, plants and animals, have advanced the research on genetic engineering plants of heavy metal resistance and accumulation, and on the functional genes (e . g. gsh1, MerA and ArsC) and their genetic transformated plants. These studies demonstrated commercialization potentials of phytoremediation. In this paper, the molecular approach, effects and problems in gene transformation were discussed in details, and also the strategy and emphases were probed into the future research.
Biodegradation, Environmental ; Genetic Engineering ; methods ; Metals, Heavy ; metabolism ; Plants, Genetically Modified ; genetics ; metabolism ; Soil Pollutants ; metabolism

Resveratrol synthase (RS) plays a key role in resveratrol (Res) biosynthesis. RS gene has been formerly reported to be transformed into many plant species and microorganisms, and to play certain roles in metabolic and regulation processes. In this paper, the transformations of RS gene in plants, and the related changes of biological properties, such as metabolites, anti-pathogen activities, anti-radical properties, and developmental characters in transgenic plants, as well as the production of resveratrol in microbes by utilizing RS gene were summarized. Moreover, the application prospects of RS gene in bioengineering were also addressed.
Acyltransferases ; genetics ; Genetic Engineering ; Plants, Genetically Modified ; enzymology ; genetics ; Stilbenes ; metabolism

Cucumber (Cucumis sativus) is an important vegetable crop in the world. Agrobacterium-mediated transgenic technology is an important way to study plant gene functions and improve varieties. In order to further accelerate the transgenic research and breeding process of cucumber, we described the progress and problems of Agrobacterium tumefaciens-mediated transgenic cucumber, from the influencing factors of cucumber regeneration ability, genetic transformation conditions and various additives in the process. We prospected for improving the genetic transformation efficiency and safety selection markers of cucumber, and hoped to provide reference for the research of cucumber resistance breeding and quality improvement.
Agrobacterium tumefaciens ; metabolism ; Breeding ; Cucumis sativus ; genetics ; microbiology ; Plants, Genetically Modified ; microbiology ; Research ; Transformation, Genetic

OBJECTIVE: To assess the potential of transient expression of recombinant human plasminogen activator (rhPA) in plants as a cost-effective approach for recombinant rhPA production. METHODS: Tobacco mosaic virus-based expression vector pTMV rhPA-NSK and plant binary expression vector pJ Zera-rhPA were constructed by sequence synthesis and subcloning. The two vectors were inoculated on either or leaves agroinfiltration. The expression of recombinant rhPA in leaves was examined using Western blotting and ELISA, and the fibrinolysis activity of plant-produced rhPA was assessed by fibrin agarose plate assay (FAPA). RESULTS: Five to nine days after infiltration with an inoculum containing pTMV rhPA-NSK, necrosis appeared in the infiltrated area on the leaves of both plants, but intact recombinant rhPA was still present in the necrotic leaf tissues. The accumulation level of recombinant rhPA in infiltrated leaves was significantly higher than that in leaves ( < 0.05). The yield of recombinant rhPA was up to 0.6% of the total soluble protein (or about 60.0 μg per gram) in the fresh leaf biomass at 7 days post-inoculation. The plant-derived rhPA was bioactive to convert inactive plasminogen to active plasmin. No necrosis occurred in pJ Zera-rhPA-infiltrated leaves. The Zera-rhPA protein was partially cleaved between the site of Zera tag and rhPA sequence in both leaves. We speculated that the formation of Zera tags-induced particles in the plant cells was a dynamic process of progressive aggregation in which some of the soluble polypeptides were encapsulated in these particles. CONCLUSIONS Enzymatically active recombinant rhPA can be rapidly expressed in tobacco plants using the plant viral ampliconbased system, which offers a promising alternative for cost-effective production of recombinant rhPA.
Humans ; Plant Leaves ; Plants, Genetically Modified ; Plasminogen ; Plasminogen Activators ; metabolism ; Recombinant Proteins ; Tobacco

Recombinant proteins provide new means for disease treatment, while creating considerable economic benefits. Using commercial crops (mainly tobacco), cereal crops, legumes, and vegetable crops to produce recombinant proteins with medicinal value is a hot-spot for research in "molecular farming". Although many recombinant proteins have been expressed in plants, only a small number have been successfully put into use. To overcome the problems that greatly hamper the development of recombinant protein production in plants, researchers have improved expression systems to increase the yield of recombinant proteins. Starting from analyzing the problems of low yield and/or low biological activity of recombinant proteins produced by plants, the optimization strategies to solve these problems were reviewed, and future research directions for improving the yield of recombinant proteins produced by plants were proposed.
Crops, Agricultural/genetics* ; Plant Proteins/metabolism* ; Plants, Genetically Modified/genetics* ; Recombinant Proteins ; Tobacco/genetics*

Plants provide an immense reservoir of natural secondary metabolites. Secondary metabolites and those involved enzymes accumulate in various compartments in specific plant tissues. The biosynthesis of diverse groups of secondary metabolites is often complicated, tightly controlled via network interconnections, metabolite levels, metabolite channeling and multi-enzyme complexes, and so on. Secondary metabolite profiles could be genetically altered by two strategies, i.e. single gene modification and multiple gene modification; which thus has opened a feasible and prospective platform for secondary chemicals production in plant.
Gene Expression Regulation, Plant ; Phytochemicals ; biosynthesis ; genetics ; Plants ; genetics ; metabolism ; Plants, Genetically Modified ; genetics ; metabolism ; Secondary Metabolism ; genetics ; Transformation, Genetic

Plant can be used as bioreactor for heterogenous protein expression. We reviewed different expression systems of plant bioreactor as well as recent relevant developments. In addition, we discussed perspectives in combination with our own experience.
Bioreactors ; microbiology ; Biotechnology ; trends ; Plants ; genetics ; metabolism ; Plants, Genetically Modified ; metabolism ; Protein Engineering ; methods ; Recombinant Proteins ; biosynthesis ; genetics

OBJECTIVETo investigate the biotransformation of daphnetin by suspension transgenic hairy root of Polygonum multiflorum and provide a biotechnological method for large-scale production of the daphnetin-8-O-beta-D-glucoside using this new culture system.

METHODDaphnetin was added into the media of suspension to culture 36 h. The biotransformation product was detected with TLC and HPLC, and isolated by various chromatographic methods. The influence of co-cultured time on conversion ratio, content of degradation product and the reason for the degradation of product II were investigated using HPLC.

RESULTOne biotransformation product, daphnetin-8-O-beta-D-glucoside, was obtained, the optimal co-cultured time in suspension hairy root of P. multiflorum was 36 h with the highest biotransformation molar ratio of 32.11%, the sucrose medium (sucrose-only) can increase the biotransformation molar ratio to 72.44%. The result demonstrated that the degradation products of the product II was induced by the MS medium.

CONCLUSIONThe potential application of suspension transgenic hairy root of P. multflorum in the sucrose-only medium on generating daphnetin-8-Obeta-D- glucoside could be prospective.

Biotransformation ; Coculture Techniques ; Glucosides ; metabolism ; Plant Roots ; genetics ; metabolism ; Plants, Genetically Modified ; Polygonum ; genetics ; metabolism ; Umbelliferones ; metabolism

In order to improve the salt tolerance of banana NHX genes, we cloned a MaNHX5 gene from Musa acuminata L. AAA group and predicted the key salt-tolerant amino acid sites and mutant protein structure changes of MaNHX5 by using bioinformatics tools. The 276-position serine (S) of MaNHX5 protein was successfully mutated to aspartic acid (D) by site-directed mutagenesis, and the AXT3 salt-sensitive mutant yeast was used for a functional complementation test. The results showed that after the mutated MaNHX5 gene was transferred to AXT3 salt-sensitive mutant yeast, the salt tolerance of the mutant yeast was significantly improved under 200 mmol/L NaCl treatment. It is hypothesized that Ser276 of MaNHX5 protein plays an important role in the transport of Na⁺ across the tonoplast.
Amino Acids/metabolism* ; Gene Expression Regulation, Plant ; Musa/metabolism* ; Plant Proteins/metabolism* ; Plants, Genetically Modified ; Saccharomyces cerevisiae/metabolism*

The expression of plant gene is controlled by its promoter. The isolation and the function analysis of promoter are important for studying the genetic engineering and the regulation expression of plant genes. In this paper, we cloned a promoter, 0s252, which was predicted to be highly expressed in the stem of rice from the EST database. After the construction of the Os252::GUS expression vector, it was transformed into rice. The integration of transgenes into transgenic rice genome was confirmed through PCR analysis. X-Gluc staining showed that Os252 can promote GUS gene expression in leaf, stem and matured seed. GUS enzyme activities driven by Os252 promoter in leaf and seed are about 190% and 250% of that driven by the 35S promoter. Thus, the Os252 promoter can be applied for rice genetic engineering.
Gene Expression Regulation, Plant ; Oryza ; genetics ; metabolism ; Plant Proteins ; genetics ; Plants, Genetically Modified ; genetics ; metabolism ; Promoter Regions, Genetic ; genetics