共查询到20条相似文献,搜索用时 31 毫秒
1.
Molecular strategies for gene containment in transgenic crops 总被引:36,自引:0,他引:36
Daniell H 《Nature biotechnology》2002,20(6):581-586
The potential of genetically modified (GM) crops to transfer foreign genes through pollen to related plant species has been cited as an environmental concern. Until more is known concerning the environmental impact of novel genes on indigenous crops and weeds, practical and regulatory considerations will likely require the adoption of gene-containment approaches for future generations of GM crops. Most molecular approaches with potential for controlling gene flow among crops and weeds have thus far focused on maternal inheritance, male sterility, and seed sterility. Several other containment strategies may also prove useful in restricting gene flow, including apomixis (vegetative propagation and asexual seed formation), cleistogamy (self-fertilization without opening of the flower), genome incompatibility, chemical induction/deletion of transgenes, fruit-specific excision of transgenes, and transgenic mitigation (transgenes that compromise fitness in the hybrid). As yet, however, no strategy has proved broadly applicable to all crop species, and a combination of approaches may prove most effective for engineering the next generation of GM crops. 相似文献
2.
Transgenic plant technology provides a powerful tool to improve abiotic stress tolerance of crop plants. However, introgression of stress tolerance genes into weedy relatives may increase the potential for persistence and invasiveness, resulting in undesirable ecological consequences. A variety of gene confinement strategies have been developed to reduce unwanted transgene movement. In this review, we discuss some of these strategies, such as male and female sterility, GeneSafe?, parthenocarpy, chloroplast transformation and gene deletor technologies. In the case of the gene deletor technology, all transgenes from pollen, seeds, fruits or other organs may be eliminated once the transgene functions are no longer needed at the stage when the presence of the transgene becomes a cause for ecological or public concern. The gene deletor and other technologies can be useful to reduce unintended dispersal of stress tolerance genes and thus may facilitate commercialization of transgenic crops with enhanced tolerance to abiotic stresses. 相似文献
3.
Forest tree biotechnology 总被引:12,自引:0,他引:12
The past year has seen the fruits of biotechnological manipulation of forest trees approach commercial application. Advances in somatic embryogenesis have brought mass clonal propagation of the top commercial trees closer to reality, and efficient gene transfer systems have been developed for a number of conifers and hardwoods. Radical alterations in the quantity and quality of lignin in wood have been shown to be possible in softwoods and hardwoods through identification of naturally occurring mutants, as well as by engineering the lignin biosynthetic pathway with transgenes. The potential environmental and social impacts of the release of transgenic trees have become an increasingly contentious issue that will require more attention if we are to use these technologies to their full advantage. 相似文献
4.
Recent advances in the genetic transformation of trees 总被引:18,自引:0,他引:18
As the commercial production of transgenic annual crops becomes a reality in many parts of the world, many people wonder if the genetic engineering of perennial trees will allow their eventual commercialization. Not long ago, trees were considered to be recalcitrant material for most molecular biology techniques, including genetic transformation. However, transgenes for shortening the juvenile phase or for phytoremediation purposes have now been incorporated, and the alteration of lignin biosynthesis and increased cellulose accumulation in forest trees have also been accomplished. For long-lived tree species, new questions arise regarding the stability of integration and expression of foreign genes. Biosafety considerations, including transgene dispersion through the pollen and advances in strategies to avoid this, are also important. 相似文献
5.
Estefania Elorriaga Richard Meilan Cathleen Ma Jeffrey S. Skinner Elizabeth Etherington Amy Brunner Steven H. Strauss 《Tree Genetics & Genomes》2014,10(6):1583-1593
The field performance of genetic containment technologies–considered important for certain uses of transgenic trees in forestry–is poorly known. We tested the efficiency of a barnase gene driven by the TA29 tapetum-dominant promoter for influencing growth rate and inducing male sterility in a field trial of transgenic hybrid poplar (Populus tremula?×?Populus tremuloides). When the growth of 18 transgenic insertion events with the sterility transgene were compared to non-transgenic controls after two growing seasons, they grew 40 % more slowly in stem volume, and all but one transgenic event grew significantly more slowly than the control. In contrast, when we compared the growth of transgenic trees containing four kinds of β-glucuronidase (GUS) reporter gene constructs to non-transgenic trees—all of which had been produced using the same transformation method and poplar clone and grown at the same field site—there were no statistically significant differences in growth after three growing seasons. In 2 years where gross pollen release from catkins was monitored and found to be abundant in the control, no pollen was visible in the transgenic trees; microscopy suggested the cause was tapetal collapse and revealed the presence of a very few normal-sized pollen grains of unknown viability. In two additional years when viable, well-formed pollen was microscopically documented in controls, and no pollen could be observed in any transgenic trees. We conclude that this construct resulted in robust and possibly complete male sterility that was stable over 4 years in the field. 相似文献
6.
林木基因克隆研究进展 总被引:1,自引:0,他引:1
林木种质资源丰富, 种质间遗传差异大, 控制林木重要性状的基因克隆及转化对培育优良林木新品种具有很强的实用价值, 但许多具有潜在应用价值的林木基因未得到充分发掘和有效分离。近年来, 随着各种不同林木cDNA文库的建立, 大规模随机EST测序技术的运用以及克隆技术的不断完善, 特别是毛果杨(Populus trichocarpa)基因组测序计划的完成, 大量与林木重要性状相关的基因被分离和鉴定。这些重要基因的获得为利用转基因技术培育高产、优质、抗逆、抗病虫害的林木新品种奠定了一定的基础。该文综述了20多年来国内外林木基因克隆的研究进展, 对基因克隆及其应用过程中亟待解决的问题进行了讨论, 并对其发展趋势进行展望。 相似文献
7.
We have identified 53 DNA (single nucleotide, microsatellite, and insertion-deletion) polymorphisms within 12 candidate genes potentially involved in ecological differences between Populus alba and P. tremula, two hybridizing European forest trees. The genes represent candidates for functional roles associated with abiotic or biotic stress response, cross-talk, phenology, and leaf development. Distributions within sequences, intraspecific levels of diversity, and genetic divergence (F(ST) ) between species are reported for each polymorphism, as are haplotype frequencies for each gene. The markers will be used for population genomic studies of the barrier to gene flow between these two ecologically divergent forest trees. 相似文献
8.
Mulkh Raj Ahuja 《Trees - Structure and Function》2009,23(6):1125-1135
Transgenics from several forest tree species, carrying a number of commercially important recombinant genes, have been produced,
and are undergoing confined field trials in a number of countries. However, there are questions and issues regarding stability
of transgene expression and transgene dispersal that need to be addressed in long-lived forest trees. Variation in transgene
expression is not uncommon in the primary transformants in plants, and is undesirable as it requires screening a large number
of transformants in order to select transgenic lines with acceptable levels of transgene expression. Therefore, the current
focus of plant transformation is toward fine tuning of transgene expression and stability in the transgenic forest trees.
Although a number of studies have reported a relatively stable transgene expression for several target traits, including herbicide
resistance, insect resistance, and lignin modification, there was also some unintended transgene instability in the genetically
modified (GM) forest trees. Transgene dispersal from GM trees to feral forest populations and their containment remain important
biological and regulatory issues facing commercial release of GM trees. Containment of transgenes must be in place to effectively
prevent escape of transgenic pollen, seed, and vegetative propagules in economically important GM forest trees before their
commercialization. Therefore, it is important to devise innovative technologies in genetic engineering that lead to genetically
stable transgenic trees not only for qualitative traits (herbicide resistance, insect resistance), but also for quantitative
traits (accelerated growth, increased height, increased wood density), and also prevent escape of transgenes in the forest
trees. 相似文献
9.
降低转基因植物外源基因扩散的分子策略 总被引:1,自引:0,他引:1
转基因植物可以通过花粉或种子将外源基因转移到其他植物,从而对生态环境造成潜在的危害。如何降低外源基因的扩散已引起了人们的极大关注。目前降低外源基因扩散的方法主要有叶绿体转化、花粉不育、种子不育、闭花受精、无融合生殖、暂时性控制及转基因缓和等。主要对各种方法的原理和优缺点及目前的使用情况进行综述。Abstract: Transgenic plants can transfer foreign genes through pollen or seed to related plant species. This may cause potential harm to ecological environment. How to decrease the gene flow is drawing a growing public attention. The approaches for decreasing the gene flow include chloroplast transformation, pollen sterility, seed sterility, cleistogamy, apomixis, temporal control, and transgenic mitigation. The theoretical basis, advantages and disadvantages, and usage status of these approaches are presented in this review. 相似文献
10.
Moyle LC 《The Journal of heredity》2007,98(2):123-135
I compare the genetic basis of quantitative traits that potentially contribute to pre- and postzygotic isolation between the plant species Solanum lycopersicum (formerly Lycopersicon esculentum) and Solanum habrochaites (formerly Lycopersicon hirsutum), using quantitative trait loci (QTL) mapping in a set of near-isogenic lines. Putative prezygotic isolating traits include flower size, flower shape, stigma exertion, and inflorescence length, that can influence pollinator preferences and/or selfing rates, and therefore gene flow between divergent types. Postzygotic isolating traits are hybrid pollen and seed sterility. Three substantive results emerge from these analyses. First, the genetic basis of floral differentiation appears to be somewhat less complex than the genetic basis of postzygotic hybrid sterility, although these differences are very modest. Second, there is little evidence that traits for floral differentiation are causally or mechanistically associated with hybrid sterility traits in this species cross. Third, there is little evidence that hybrid sterility QTL are more frequently associated with chromosomal centromeric regions, in comparison to floral trait QTL, a prediction of centromeric drive models of hybrid sterility. Although genome-wide associations are not evident in this analysis, several individual chromosomal regions that contain clusters of QTL for both floral and sterility traits, or that indicate hybrid sterility effects at centromere locations, warrant further fine-scale investigation. 相似文献
11.
12.
Burgess DG Ralston EJ Hanson WG Heckert M Ho M Jenq T Palys JM Tang K Gutterson N 《The Plant journal : for cell and molecular biology》2002,31(1):113-125
Ablation of cells by the controlled expression of a lethal gene can be used to engineer plant traits such as male sterility and disease resistance. However, it may not be possible to achieve sufficient specificity of expression to prevent secondary effects in non-targeted tissues. In this paper we demonstrate that the extracellular ribonuclease, barnase, can be engineered into two complementary fragments, allowing overlapping promoter specificity to be used to enhance targeting specificity. Using a transient system, we first show that barnase can be split into two inactive peptide fragments, that when co-expressed can complement each other to reconstitute barnase activity. When a luciferase reporter gene was introduced into plant cells along with genes encoding both partial barnase peptides, a substantial reduction in luciferase activity was seen. Cytotoxicity of the reconstituted barnase was demonstrated by crossing together parents constitutively expressing each of the barnase fragments, then assaying their progeny for the presence of both partial barnase genes. None of over 300 tomato seeds planted resulted in a viable progeny that inherited both transgenes. When expression of the partial barnase genes was instead targeted to the tapetum, male sterility resulted. All 13 tomato progeny that inherited both transgenes were male sterile, whereas the three progeny inheriting only the N-terminal barnase gene were male fertile. Finally, we describe how male sterility generated by this type of two-component system can be used in hybrid seed production. 相似文献
13.
John M. Marshall 《Journal of theoretical biology》2009,258(2):250-265
Mosquito-borne diseases such as malaria and dengue fever continue to be a major health problem through much of the world. Several new potential approaches to disease control utilize gene drive to spread anti-pathogen genes into the mosquito population. Prior to a release, these projects will require trials in outdoor cages from which transgenic mosquitoes may escape, albeit in small numbers. Most genes introduced in small numbers are very likely to be lost from the environment; however, gene drive mechanisms enhance the invasiveness of introduced genes. Consequently, introduced transgenes may be more likely to persist than ordinary genes following an accidental release. Here, we develop stochastic models to analyze the loss probabilities for several gene drive mechanisms, including homing endonuclease genes, transposable elements, Medea elements, the intracellular bacterium Wolbachia, engineered underdominance genes, and meiotic drive. We find that Medea and Wolbachia present the best compromise between invasiveness and containment for the six gene drive systems currently being considered for the control of mosquito-borne disease. 相似文献
14.
Lenka Rucká Jan Nešvera Miroslav Pátek 《World journal of microbiology & biotechnology》2017,33(9):174
Biodegradation of phenolic compounds is a promising alternative to physical and chemical methods used to remove these toxic pollutants from the environment. The ability of various microorganisms to metabolize phenol and its derivatives (alkylphenols, nitrophenols and halogenated derivatives) has therefore been intensively studied. Knowledge of the enzymes catalyzing the individual reactions, the genes encoding these enzymes and the regulatory mechanisms involved in the expression of the respective genes in bacteria serves as a basis for the development of more efficient degraders of phenols via genetic engineering methods. Engineered bacteria which efficiently degrade phenolic compounds were constructed in laboratories using various approaches such as cloning the catabolic genes in multicopy plasmids, the introduction of heterologous genes or broadening the substrate range of key enzymes by mutagenesis. Efforts to apply the engineered strains in in situ bioremediation are problematic, since engineered strains often do not compete successfully with indigenous microorganisms. New efficient degraders of phenolic compounds may be obtained by complex approaches at the organism level, such as genome shuffling or adaptive evolution. The application of these engineered bacteria for bioremediation will require even more complex analysis of both the biological characteristics of the degraders and the physico-chemical conditions at the polluted sites. 相似文献
15.
Genetic engineering for complex or combined traits requires the simultaneous expression of multiple genes, and has been considered as the bottleneck for the next generation of genetic engineering in plants. Minichromosome technology provides one solution to the stable expression and maintenance of multiple transgenes in one genome. For example, minichromosomes can be used as a platform for efficient stacking of multiple genes for insect, bacterial and fungal resistances together with herbicide tolerance and crop quality traits. All the transgenes would reside on an independent minichromosome, not linked to any endogenous genes; thus linkage drag can be avoided. Engineered minichromosomes can be easily constructed by a telomere-mediated chromosomal truncation strategy. This approach does not rely on the cloning of centromere sequences, which are species-specific, and bypasses the any complications of epigenetic components for centromere specification. Thus, this technique can be easily extended to all plant species. The engineered minichromosome technology can also be used in combination with site-specific recombination systems to facilitate the stacking of multiple transgenes. 相似文献
16.
Directed microspore-specific recombination of transgenic alleles to prevent pollen-mediated transmission of transgenes 总被引:6,自引:0,他引:6
A major challenge for future genetically modified (GM) crops is to prevent undesired gene flow of transgenes to plant material intended for another use. Recombinase-mediated auto excision of transgenes directed by a tightly controlled microspore-specific promoter allows efficient removal of either the selectable marker gene or of all introduced transgenes during microsporogenesis. This way, transgene removal becomes an integral part of the biology of pollen maturation, not requiring any external stimulus such as chemical induction by spraying. We here show the feasibility of engineering transgenic plants to produce pollen devoid of any transgene. Highly efficient excision of transgenes from tobacco pollen was achieved with a potential failure rate of at most two out of 16 800 seeds (0.024%). No evidence for either premature activation or absence of activation of the recombinase system was observed under stress conditions in the laboratory. This approach can prevent adventitious presence of transgenes in non-GM crops or related wild species by gene flow. Such biological containment may help the deployment and management of coexistence practices to support consumer choice and will promote clean molecular farming for the production of high-value compounds in plants. 相似文献
17.
Jatropha tanjorensis , an interspecific hybrid between Jatropha curcas and Jatropha gossypifolia , is reported to be a sterile hybrid, which has drastically limited its natural propagation. To determine the probability of existing sterility, floral biology was carried out in 30 trees of six accessions during 2007–2008. The results were explored in terms of morphological and anatomical details of floral abnormality. Although unisex flowers are a characteristic feature of the genus, unusual bisexual flowers with pseudostamens or staminodes were also present. Petalody of the stamen was frequently observed in most of the floral samples. Anther lobes were flat, cordate, fibrous, and some had one or more callus-like structures and contained a few sterile pollen grains. In polypistillody, pistils were irregular in shape and position or were fused with the staminodes. Frequently occurring forms of these floral abnormalities as well as unusual hermaphrodity were highly responsible for the sterility of J. tanjorensis . 相似文献
18.
Gene flow by pollen dispersal from forestry plantations containing introduced species, provenances or selected elite breeding
material may impact on local native forest by changing the genetic diversity, introducing new genes or gene combinations,
or causing the extinction of rare genotypes in adjacent native forest areas. Patterns of pollen flow can be used to assess
the risk of genetic pollution of native forest areas from nearby plantations. Pollen flow in an artificial population of Eucalyptus grandis was estimated using molecular markers and paternity analysis. Microsatellite genotyping was used to identify pollen parents
of progeny arrays from six mother trees. Of 329 progeny analysed, 178 (54%) were assigned to pollen parents within the population.
Pollen parents located within the population were between 0–192 m from the respective mother trees, with an average pollination
distance of 57.96 m. Pollination of mother trees was outcrossed, not by nearest neighbours, and displayed a preference for
inter-provenance matings within the population. Progeny that could not be assigned pollen parents within the population (46%)
were assumed to have resulted from pollen immigration from external sources. These pollen flow parameters provide useful information
about the dynamics of pollen movement within E. grandis populations and may be used in risk assessment of gene flow from plantations to adjacent areas of native forest. 相似文献
19.
Fate of transgenes in the forest tree genome 总被引:1,自引:0,他引:1
M. Raj Ahuja 《Tree Genetics & Genomes》2011,7(2):221-230
During the last two decades, genetic engineering (GE) has been progressing at a steady pace in the forest trees. Transgenic
trees carrying a variety of different transgenes have been produced, and are undergoing confined field trials in the world.
However, there are questions regarding stability of transgene expression, and transgene escape that need to be addressed in
the long-lived forest trees. Although relatively stable transgene expression has been reported for several target traits,
including herbicide resistance, insect resistance, and lignin reduction in the vegetative propagules of several forest tree
species, there were still unintended unstable events in transgenic plants. Long-term stability of transgene expression involved
in these traits and others affecting yield (impacting growth) would be desirable in the vegetative propagules, and also in
the generative progeny of the forest trees. Transgene escape through pollen, seed, and vegetative propagules from GE trees
to native forest populations, although inevitable, remains an important regulatory issue. However, it may be possible to manage/minimize
the risk of transgene spread via isolation in confined areas, and use of incompatible genotypes of feral tree populations
in the vicinity of transgenic forest trees. Therefore, it is desirable to produce genetically stable transgenic trees, and
have biocontainment measures in place for testing and deployment of the GE forest trees. Toward these goals (transgene stability
and containment), innovative biotech strategies are being actively pursued, with reasonable success, in forest trees. 相似文献
20.
Li W Zeng R Zhang Z Ding X Zhang G 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(7):915-922
The partial pollen abortion of hybrids between the indica and japonica subspecies of Asian cultivated rice is one of the major barriers in utilizing intersubspecific heterosis in hybrid rice breeding.
Although a single hybrid pollen sterility locus may have little impact on spikelet fertility, the cumulative effect of several
loci usually leads to a serious decrease in spikelet fertility. Isolating of the genes conferring hybrid pollen sterility
is necessary to understand this phenomenon and to overcome the resulting genetic barrier. In this study, a new locus for F1 pollen sterility, S-d, was identified on the short arm of chromosome 1 by analyzing the genetic effect of substituted segments of the near-isogenic
line E11-5 derived from the japonica variety Taichung 65 (recurrent parent) and the indica variety Dee-geo-woo-gen (donor parent). The S-d locus was first mapped to a 0.8 cM interval between SSR markers PSM46 and PSM80 using a F2 population of 125 individuals. The flanking markers were then used to identify recombinants from a population of 2,160 plants
derived from heterozygotes of the primary F2 population. Simultaneously, additional markers were developed from genomic sequence divergence in this region. Analysis of
the recombinants in the region resulted in the successful mapping of the S-d locus to a 67-kb fragment, containing 17 predicted genes. Positional cloning of this gene will contribute to our understanding
of the molecular basis for partial pollen sterility of intersubspecific F1 hybrids in rice. 相似文献