Genetic modification; the development of transgenic ornamental plant varieties

Plant transformation technology (hereafter abbreviated to GM, or genetic modification) has been used to develop many varieties of crop plants, but only a few varieties of ornamental plants. This disparity in the rate and extent of commercialisation, which has been noted for more than a decade, is not because there are no useful traits that can be engineered into ornamentals, is not due to market potential and is not due to a lack of research and development activity. The GM ornamental varieties which have been released commercially have been accepted in the marketplace. In this article, progress in the development of transgenic ornamentals is reviewed and traits useful to both consumers and producers are identified. In considering possible factors limiting the release of genetically modified ornamental products it is concluded that the most significant barrier to market is the difficulty of managing, and the high cost of obtaining, regulatory approval.     

Transgenic trees for a new era

Summary Traditional breeding has been widely used in forestry. However, this technique is inefficient because trees have a long and complex life cycle that is not amenable to strict control by man. Fortunately, the development of genetic engineering is offering new ways of breeding and allowing the incorporation of new traits in plant species through the introduction of foreign genes (transgenes). The introduction of selected traits can be used to increase the productivity and commercial value of trees and other plants. For example, some species have been endowed with resistance to herbicide and pathogens such as insects and fungi. Also, it has been possible to introduce genes that modify development and wood quality, and induce sexual sterility. The development of transgenic trees has required the implementation of in vitro regeneration techniques such as organogenesis and somatic embryogenesis. Release of transgenic species into the agricultural market requires a standardized biosafety regulatory frame and effective communication between the scientific community and society to dissipate the suspicions associated with transgenic products.     

转基因鱼离市场还有多远

根据本实验室转基因鱼育种研究的现状,讨论了“转基因鱼离市场还有多远”这一令人关注的问题。转草鱼生长激素重组基因（ＣＡｇｃＧＨ）鲤鱼具有明显的快速生长和饵料节省效应,鱼体有高干物质含量及高蛋白低脂肪的生化组成,是一种优质食用鱼。把一种鱼的基因转移到另一种鱼,即转“全鱼”基因后,受体鱼基因组改变的程度,仅相当于两种杂交的１０万分之一左右,因而它对水生态系统的胁迫作用轻微的,充其量可视为与相应杂交鱼实质     

Current trends in the global market of transgenic plants and environmental safety issues

The world market for the first generation of transgenic crops (insecticidal and herbicide-resistant plants) has been expanding since 2012, mostly owing to developing countries. The cautious attitude in the majority of economically developed countries to the first-generation transgenic agricultural crops is due to several objective circumstances: the negative impact of insecticidal Bt-crops on useful and endangered invertebrate species, the allergenic properties of Bt-toxin for humans, toxicity of glyphosate to humans and animals, the widely spreading resistance of weeds to glyphosate, the increasing resistance of–harmful–insects to insecticidal Bt-plants, the danger of–genetic pollution–of aboriginal plant varieties, and the flow of herbicide resistance traits to weed plants.     

Minimizing the time and cost of production of transgenic alfalfa libraries using the highly efficient completely sequenced vector pPZP200BAR

Alfalfa is the most important forage legume worldwide. However, similar to other minor forage crops, it is usually harvested along with weeds, which decrease its nutrient quality and thus reduce its high value in the market. In addition, weeds reduce alfalfa yield by about 50 %. Although weeds are the limiting factor for alfalfa production, little progress has been made in the incorporation of herbicide-tolerant traits into commercial alfalfa. This is partially due to the high times and costs needed for the production of vast numbers of transgenic alfalfa events as an empirical approach to bypass the random transgenic silencing and for the identification of an event with optimal transgene expression. In this focus article, we report the complete sequence of pPZP200BAR and the extremely high efficiency of this binary vector in alfalfa transformation, opening the way for rapid and inexpensive production of transgenic events for alfalfa improvement public programs.     

Gene transfer technology in aquaculture

The gene transfer technique, transgenesis, has permitted the transfer of genes from one organism to another to create new lineages of organisms with improvement in traits important to aquaculture. Genetically modified organisms (GMOs), therefore, hold promise for producing genetic improvements, such as enhanced growth rate, increased production and efficiency, disease resistance and expanded ecological ranges. The basic procedure to generate transgenic fish for aquaculture includes: (1) design and construction of transgenic DNA; (2) transfer of the gene construct into fish germ cells; (3) screening for transgenic fish; (4) determination of transgene expression and phenotype; (5) study of inheritance; and (6) selection of stable lines of transgenics.GMOs offer economic benefits, but also pose environmental threats. Optimising the mix of benefits and risks is of fundamental importance. The potential economic benefits of transgenic technology to aquaculture are obvious. Transgenic fish production has the goal of producing food for human consumption; thus the design of genetic constructs must take into consideration the potential risks to consumer health, as well as marketing strategies and product acceptance in the market.     

RNAi介导的OsBTF3基因沉默及其对水稻籽粒相关性状的影响

为了创制OsBTF3基因沉默的水稻植株、验证该基因在水稻籽粒相关性状中的功能、评价其在水稻遗传改良中潜在的应用价值,设计和合成OsBTF3基因序列的引物、扩增部分基因片段,构建RNAi基因沉默载体、通过农杆菌介导转化愈伤组织、植株再生、潮霉素抗性筛选和PCR验证、定量分析OsBTF3基因表达量,测定转基因水稻籽粒相关性状。结果表明,成功地获得了20个T1代OsBTF3-RNAi转基因株系,OsBTF3基因表达量得到显著的抑制和干扰,抑制效果平均达到85%;与野生型对照株相比,5个所测定RNAi转基因株系的穗长、穗粒数、千粒重和穗粒重等籽粒相关性状明显地减小或降低。因此,RNAi介导的基因沉默导致了OsBTF3基因表达水平抑制以及在籽粒性状中的功能缺失;OsBTF3可能是一个调控水稻籽粒相关性状重要的功能基因。     

Evaluating the fitness of human lysozyme transgenic dairy goats: growth and reproductive traits

While there are many reports in the literature describing the attributes of specific applications of transgenic animals for agriculture, there are relatively few studies focusing on the fitness of the transgenic animals themselves. This work was designed to gather information on genetically modified food animals to determine if the presence of a transgene can impact general animal production traits. More specifically, we used a line of transgenic dairy goats expressing human lysozyme in their mammary gland to evaluate the reproductive fitness and growth and development of these animals compared to their non-transgenic counterparts and the impact of consuming a transgenic food product, lysozyme-containing milk. In males, none of the parameters of semen quality, including semen volume and concentration, total sperm per ejaculate, sperm morphology, viability and motility, were significantly different between transgenic bucks and non-transgenic full-sib controls. Likewise, transgenic females of this line did not significantly differ in the reproductive traits of gestation length and litter size compared to their non-transgenic counterparts. To evaluate growth, transgenic and non-transgenic kid goats received colostrum and milk from either transgenic or non-transgenic does from birth until weaning. Neither the presence of the transgene nor the consumption of milk from transgenic animals significantly affected birth weight, weaning weight, overall gain and post-wean gain. These results indicate that the analyzed reproductive and growth traits were not regularly or substantially impacted by the presence or expression of the transgene. The evaluation of these general parameters is an important aspect of defining the safety of applying transgenic technology to animal agriculture.     

Genetically modified crops for the bioeconomy: meeting public and regulatory expectations

As the United States moves toward a plant-based bioeconomy, a large research and development effort is focused on creating new feedstocks to meet biomass demand for biofuels, bioenergy, and specialized bioproducts, such as industrial compounds and biomaterial precursors. Most bioeconomy projections assume the widespread deployment of novel feedstocks developed through the use of modern molecular breeding techniques, but rarely consider the challenges involved with the use of genetically modified crops, which can include hurdles due to regulatory approvals, market adoption, and public acceptance. In this paper we consider the implications of various transgenic crops and traits under development for the bioeconomy that highlight these challenges. We believe that an awareness of the issues in crop and trait selection will allow developers to design crops with maximum stakeholder appeal and with the greatest potential for widespread adoption, while avoiding applications unlikely to meet regulatory approval or gain market and public acceptance. The views presented here are those of the authors and do not necessarily represent the views of the US government.     

Glyphosate-drift but not herbivory alters the rate of transgene flow from single and stacked trait transgenic canola (Brassica napus) to nontransgenic B. napus and B. rapa

? Transgenic plants can offer agricultural benefits, but the escape of transgenes is an environmental concern. In this study we tested the hypothesis that glyphosate drift and herbivory selective pressures can change the rate of transgene flow between the crop Brassica napus (canola), and weedy species and contribute to the potential for increased transgene escape risk and persistence outside of cultivation. ? We constructed plant communities containing single transgenic B. napus genotypes expressing glyphosate herbicide resistance (CP4 EPSPS), lepidopteran insect resistance (Cry1Ac), or both traits ('stacked'), plus nontransgenic B. napus, Brassica rapa and Brassica nigra. Two different selective pressures, a sublethal glyphosate dose and lepidopteran herbivores (Plutella xylostella), were applied and rates of transgene flow and transgenic seed production were measured. ? Selective treatments differed in the degree in which they affected gene flow and production of transgenic hybrid seed. Most notably, glyphosate-drift increased the incidence of transgenic seeds on nontransgenic B. napus by altering flowering phenology and reproductive function. ? The findings of this study indicate that transgenic traits may be transmitted to wild populations and may increase in frequency in weedy populations through the direct and indirect effects of selection pressures on gene flow.     

转拟南芥NPR1基因桂99 T3代植株的抗病性及农艺性状表现

以转拟南芥AtNPR1基因的恢复系品种桂99T3代纯合株系为材料,考查其农艺性状及其抗病性,并比较转基因植株与桂99侵染水稻白叶枯病菌后的农艺性状。结果表明:转基因植株表现出对水稻白叶枯病的抗性显著增强77%以上;穗长、剑叶长、有效穗数、一次枝梗数、每穗实粒数、单株产量和谷粒宽等农艺性状与未转基因桂99无显著差别。在受到水稻白叶枯病菌侵染后,转基因植株的一次枝梗数、每穗粒数、每穗实粒数和单株产量等方面均比对照桂99高出13%～78%。说明AtNPR1基因增强了水稻的抗病能力,从而降低了病害引起的产量损失。转基因植株的恢复力不受影响,稻米品质比桂99更加优良。本工作为转基因水稻抗病育种的研究奠定了基础。     

Recombinase-mediated gene stacking as a transformation operating system

The current method for combining transgenes into a genome is through the assortment of independent loci, a classical operating system compatible with transgenic traits created by different developers, at different times and/or through different transformation techniques. However, as the number of transgenic loci increases over time, increasingly larger populations are needed to find the rare individual with the desired assortment of transgenic loci along with the non-transgenic elite traits. Introducing a transgene directly into a field cultivar would bypass the need to introgress the engineered trait. However, this necessitates separate transformations into numerous field cultivars, along with the characterization and regulatory approval of each independent transformation event. Reducing the number of segregating transgenic loci could be achieved if multiple traits are introduced at the same time, a preferred option if each of the many traits is new or requires re-engineering. If re-engineering of previously introduced traits is not needed, then appending a new trait to an existing locus would be a rational strategy. The insertion of new DNA at a known locus can be accomplished by site-specific integration, through a host-dependent homology-based process, or a heterologous site-specific recombination system. Here, we discuss gene stacking through the use of site-specific recombinases.     

T-DNA-induced mutations in transgenic plants

The review surveys experimental data on changes of individual traits in genetically modified (transgenic) plants. The attention is focused on mutations induced by T-DNA insertions upon Agrobacterium-induced transformation of dicotyledonous plants. The character of mutation appearance in transgenic plants is examined. The prospects of mutations induced by T-DNA insertions are considered.     

Field evaluation and agronomic performance of transgenic wheat

Seven transgenic lines of wheat have been evaluated under field conditions during 2 agonomic years. Four lines contained the transgenes for beta-glucuronidase ( uidA), herbicide resistance ( bar) and for one high-molecular-weight (HMW) subunit, and three lines contained only one transgene for one HMW glutenin subunit and no marker genes. Agronomic traits and yield components were studied in transgenic lines and compared with the non-transgenic parent and null segregant lines. Although phenotypic differences for many traits have been found, only heading date and the number of spikelets per spike showed clear genotypic differences for both field trials. All transgenic lines had a longer heading date than parent lines whereas the number of spikelets per spike in transgenic lines was around that for L88-31 and higher for L88-6 than the corresponding parent lines. No differences were found between lines constitutively expressing the uidA and bar genes from those which only expressed the HMW genes. We conclude that differences between transgenic lines and their parents are small, and could be eliminated by backcrossing transgenic lines with their parents and selecting for the wanted genotype.     

Production of engineered long-life and male sterile Pelargonium plants

ABSTRACT: BACKGROUND: Pelargonium is one of the most popular garden plants in the world. Moreover, it has a considerable economic importance in the ornamental plant market. Conventional cross-breeding strategies have generated a range of cultivars with excellent traits. However, gene transfer via Agrobacterium tumefaciens could be a helpful tool to further improve Pelargonium by enabling the introduction of new genes/traits. We report a simple and reliable protocol for the genetic transformation of Pelargonium spp. and the production of engineered long-life and male sterile Pelargonium zonale plants, using the pSAG12::ipt and PsEND1::barnase chimaeric genes respectively. RESULTS: The pSAG12::ipt transgenic plants showed delayed leaf senescence, increased branching and reduced internodal length, as compared to control plants. Leaves and flowers of the pSAG12::ipt plants were reduced in size and displayed a more intense coloration. In the transgenic lines carrying the PsEND1::barnase construct no pollen grains were observed in the modified anther structures, which developed instead of normal anthers. The locules of sterile anthers collapsed 3--4 days prior to floral anthesis and, in most cases, the undeveloped anther tissues underwent necrosis. CONCLUSION: The chimaeric construct pSAG12::ipt can be useful in Pelargonium spp. to delay the senescence process and to modify plant architecture. In addition, the use of engineered male sterile plants would be especially useful to produce environmentally friendly transgenic plants carrying new traits by preventing gene flow between the genetically modified ornamentals and related plant species. These characteristics could be of interest, from a commercial point of view, both for pelargonium producers and consumers.     

Gene Flow,Risk Assessment and the Environmental Release of Transgenic Plants

The release of genetically modified plants is governed by regulations that aim to provide an assessment of potential impact on the environment. One of the most important components of this risk assessment is an evaluation of the probability of gene flow. In this review, we provide an overview of the current literature on gene flow from transgenic plants, providing a framework of issues for those considering the release of a transgenic plant into the environment. For some plants gene flow from transgenic crops is well documented, and this information is discussed in detail in this review. Mechanisms of gene flow vary from plant species to plant species and range from the possibility of asexual propagation, short- or long-distance pollen dispersal mediated by insects or wind and seed dispersal. Volunteer populations of transgenic plants may occur where seed is inadvertently spread during harvest or commercial distribution. If there are wild populations related to the transgenic crop then hybridization and eventually introgression in the wild may occur, as it has for herbicide resistant transgenic oilseed rape (Brassica napus). Tools to measure the amount of gene flow, experimental data measuring the distance of pollen dispersal, and experiments measuring hybridization and seed survivability are discussed in this review. The various methods that have been proposed to prevent gene flow from genetically modified plants are also described. The current “transgenic traits” in the major crops confer resistance to herbicides and certain insects. Such traits could confer a selective advantage (an increase in fitness) in wild plant populations in some circumstances, were gene flow to occur. However, there is ample evidence that gene flow from crops to related wild species occurred before the development of transgenic crops and this should be taken into account in the risk assessment process.     

Comparison of variation in adaptive traits between wild-type and transgenic silver birch (Betula pendula) in a field trial

The use of genetic modification (GM) in tree breeding would require that GM trees are superior to currently used seed orchard seedlings in the target trait and equal in other traits. We compare the variation of silver birch (Betula pendula Roth) lines carrying a sugar beet chitinase IV gene (chiIV) with the objective to improve fungal disease resistance to the variation of wild-type genotypes in disease resistance and other adaptive traits. The genetic variation in disease resistance was at the same level in transgenic (CV_g 0.9?C19.0%) and wild-type trees (CV_g 0?C19.7%), but the resistance characteristics of the most resistant wild-type genotype were usually equal or better than those of the best transgenic line. The broad-sense heritabilities varied from very low to moderate in disease resistance in both types. Broad-sense heritabilities in growth and leaf phenology-related traits were moderate and generally higher among the transgenic than the wild-type trees. The introduction of the sugar beet chiIV gene is likely to have fitness consequences in the form of lowered growth and quality characteristics of the transgenic lines without significant improvement in disease resistance compared with the natural variation of the same traits.     

转基因植物对传粉蜂类影响的研究进展

随着转基因作物的大规模商业种植,其对非靶生物的安全性问题已经成为转基因生物风险评估的重要内容。有些转基因植物是需要蜂类传粉的显花植物．有些则可作为蜂类的食物来源。抗性转基因植物可能对蜂类产生直接和间接的影响。转基因植物的花粉或者花蜜可能对蜂类产生直接影响,测试化学杀虫剂安全性的相同方法被用来评估这种影响。很多研究测试了纯化的转基因蛋白质(如Bt,蛋白酶抑制剂)对蜜蜂和熊蜂的影响。间接影响来自于遗传转化可能使转基因植物的表型产生的异常变化,特别是花的改变。这种影响是用转基因植物进行评估的。转基因植物对蜂类的影响研究所测定的参数包括蜂类的肠道生理、取食和嗅觉学习行为、经口毒性和寿命等。对在实验室中以幼蜂或者成年蜂为对象、在封闭条件下针对蜂群的研究以及蜂类在转基因植物上的取食行为方面的研究进行了总结。结果表明,转基因植物是否对传粉蜂类产生影响以及影响的大小主要取决于转基因植物的生物学特征、转基因蛋白的性质和表达量。一般来说,Bt毒素蛋白和葡聚糖酶等蛋白质对蜂类没有影响;而某些蛋白酶抑制剂和几丁质酶则可能对蜂类产生不利影响,蜂类所摄取到这类蛋白质的剂量将决定影响的程度。然而,由于采用的研究方法各不相同,难以对不同的研究结果进行分析和比较,并得出明确的结论。