Transgene transfer and inheritance under genetic transformation in maize

Achievements are discussed regarding in genetic transformation of maize is examined from that point of view what cells, tissues and organs can be the targets for the alien gene transfer. The review of available data on genotypical peculiarities of transgenesis and inheritance of alien genes included in the maize genome are presented.     

花生遗传转化的主要方法和研究进展

花生遗传转化研究对于花生品种改良、新品种繁育具有重要意义。农杆菌介导的遗传转化法和基因枪法是花生遗传转化的主要方法。随着对花生研究的深入开展,花生的遗传转化技术也越来越成熟。介绍了农杆菌介导的遗传转化法和基因枪法在花生遗传转化研究中的应用现状及存在的问题。     

植物的遗传转化及其应用(英文)

近年来,植物遗传转化研究有了长足的发展。已经达到能够通过简单的遗传控制手段研究具有新表现型的植物,甚至达到进入商业化的程度。这些手段包括植物生物学的主要研究技术以及植物组织培养和树种改良的一些实用方法。尽管采用农瘤杆菌和鸟枪法等技术的植物遗传转化系统已经得到了广泛的应用,但是在如何开发具有能够得到控制表达的转基因高产植物方面,在如何使所得到的转基因植物远离遗传危害等方面,目前的转化系统遇到了极大的技术挑战。已经提出了各种各样的方法用于将新基因稳定地导入120多种不同植物的核基因组。本文将讨论这些遗传转化系统所需的生物学要求和实际应用方面的需求、基因转化和转基因表达的研究策略、遗传转化植物的鉴定以及转基因植物与大众的认可。本文将分为七个部分加以讨论:一、导言;二 、基因转化到细胞里的方法;三、植物遗传转化策略;四、植物遗传转化的鉴定;五、植物遗传转化的实际应用;六、转基因植物与环境;七、未来植物遗传转化的需求与发展方向。     

基因枪转化技术及其在禾谷类作物遗传转化中的应用

基因枪转化法广泛用于禾谷类作物的遗传转化研究,是目前禾谷类作物遗传转化的有效方法。简要介绍了基困枪转化法的产生与发展、转化的特点以及影响转化频率的主要因素;系统地概述了基因枪法在禾谷类作物遗传转化的应用。     

Genetic engineering of millets: current status and future prospects

This review summarizes progress on the genetic transformation of millets and discusses the future prospects for the development of improved varieties. Only a limited number of studies have been carried out on genetic improvement of millets despite their nutritional importance in supplying minerals, calories and protein. Most genetic transformation studies of millets have been restricted to pearl millet and bahiagrass and most studies have been limited to the assessment of reporter and marker gene expression. Biolistic-mediated gene delivery has been frequently used for the transformation of millets but Agrobacterium-mediated transformation is still lagging. Improved transformation of millets, allied to relevant gene targets which may offer, for example, improved nutritional quality, resistance to abiotic and biotic stresses, and resistance to fungal infection will play important roles in millet improvement.     

Genetic transformation of barley: limiting factors

This review summarizes main difficulties involved in barley (Hordeum vulgare L.) transformation. The most commonly used procedures for genetic transformation in barley are Agrobacterium tumefaciens and particle bombardment mediated methods. While different barley cultivars are used for genetic engineering with varying sensitivity, recent improvements in regeneration and transformation techniques are described and summarized. Furthermore, some of the transformation complicating factors, in particular somaclonal variation and transgene insertion sites, are discussed in more detail.     

Bacterial gene transfer by natural genetic transformation in the environment.

Natural genetic transformation is the active uptake of free DNA by bacterial cells and the heritable incorporation of its genetic information. Since the famous discovery of transformation in Streptococcus pneumoniae by Griffith in 1928 and the demonstration of DNA as the transforming principle by Avery and coworkers in 1944, cellular processes involved in transformation have been studied extensively by in vitro experimentation with a few transformable species. Only more recently has it been considered that transformation may be a powerful mechanism of horizontal gene transfer in natural bacterial populations. In this review the current understanding of the biology of transformation is summarized to provide the platform on which aspects of bacterial transformation in water, soil, and sediments and the habitat of pathogens are discussed. Direct and indirect evidence for gene transfer routes by transformation within species and between different species will be presented, along with data suggesting that plasmids as well as chromosomal DNA are subject to genetic exchange via transformation. Experiments exploring the prerequisites for transformation in the environment, including the production and persistence of free DNA and factors important for the uptake of DNA by cells, will be compiled, as well as possible natural barriers to transformation. The efficiency of gene transfer by transformation in bacterial habitats is possibly genetically adjusted to submaximal levels. The fact that natural transformation has been detected among bacteria from all trophic and taxonomic groups including archaebacteria suggests that transformability evolved early in phylogeny. Probable functions of DNA uptake other than gene acquisition will be discussed. The body of information presently available suggests that transformation has a great impact on bacterial population dynamics as well as on bacterial evolution and speciation.     

根癌农杆菌介导真菌遗传转化的研究及应用

根癌农杆菌介导转化法（Agrobacterium tumefaciens-mediated transformation,ATMT）具有转化效率高、遗传稳定、适用范围广等诸多优点,已成为真菌遗传转化研究中的强有力手段,在真菌基因资源开发、真菌性疾病研究和外源蛋白表达研究中发挥巨大作用。本文概述了根癌农杆菌转化法在真菌转化中的研究进展、技术优缺点、转化机制、实验方法和应用现状,着重介绍影响其转化效率的因素并对优化方法进行探讨,展望了该技术在真菌基因资源发掘、基因编辑等方面的应用前景,为今后真菌的遗传转化研究提供参考。     

Genetic transformation of sugar beet: evolution of theoretical and experimental approaches

The review is dedicated to several aspects of sugar beet (Beta vulgaris L.) biotechnology: in vitro cultivation, callus induction, plant regeneration and genetic transformation. Media composition, methods of plant regeneration via somatic embryogenesis and protoplast culture are analysed. The use of Agrobacterium tumefaciens and gold particle bombardment is the base for modern genetic transformation methods.     

Genetic transformation of wheat: progress during the 1990s into the Millennium

Wheat transformation technology has progressed rapidly during the past decade. Initially, procedures developed for protoplast isolation and culture, electroporation- and polyethylene glycol (PEG)-induced DNA transfer enabled foreign genes to be introduced into wheat cells. The development of biolistic (microprojectile) bombardment procedures led to a more efficient approach for direct gene transfer. More recently, Agrobacterium-mediated gene delivery procedures, initially developed for the transformation of rice, have also been used to generate transgenic wheat plants. This review summarises the considerable progress in wheat transformation achieved during the last decade. An increase in food production is essential in order to sustain the increasing world population. This could be achieved by the development of higher yielding varieties with improved nutritional quality and tolerance to biotic and abiotic stresses. Although conventional breeding will continue to play a major role in increasing crop yield, laboratory-based techniques, such as genetic transformation to introduce novel genes into crop plants, will be essential in complementing existing breeding technologies. A decade ago, cereals were considered recalcitrant to transformation. Since then, a significant research effort has been focused on cereals because of their agronomic status, leading to improved genetic transformation procedures (Bommineni and Jauhar 1997). Initially, the genetic transformation of cereals relied on the introduction of DNA into protoplasts and the subsequent production of callus from which fertile plants were regenerated. More recently, major advances have been accomplished in the regeneration of fertile plants from a range of source tissues, providing an essential foundation for the generation of transgenic plants. This review summarises procedures, vectors and target tissues used for transformation, high-lights the limitations of current approaches and discusses future trends. The citation of references is limited, where possible, to the most relevant or recent reports.     

农杆菌介导玉米遗传转化体系的研究进展

玉米(Zea maysL.)是世界上三大主要粮食作物之一,至今其遗传转化仍比较困难,目前报道有多种成功的方法,其中农杆菌(Agrobactierium tumefaciens)介导法是当前玉米遗传转化的主要方法。本文综述了农杆菌介导的玉米遗传转化研究的发展历史、存在问题和影响因素等,并对未来发展趋势进行展望。     

Genetic transformation of the blue-green bacterium,Anacystis nidulans

Evidence is presented which confirms the existence of genetic transformation in the blue-green bacterium, Anacystis nidulans. This process has been demonstrated for three mutations: streptomycin resistance, a phenylalanine requirement and an ornithine requirement. The optimal conditions under which transformation occurs are also investigated, and the potential of this system for genetic mapping is discussed.This work was submitted by K. G. O. in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Biology, Bryn Mawr College.     

影响农杆菌介导的杨树遗传转化技术的因素

杨属树种是农杆菌的天然寄主之一,但木本植物一般再生能力较差,如何提高杨树的遗传转化频率就成为目前研究者最为关心的问题。本文结合农杆菌介导杨树遗传转化研究的最新进展和我们的实际工作对农杆菌的遗传转化原理、转移方法、以及影响农杆菌转化的因素进行了全新而深入的论述,并针对如何提高木本植物的转化频率,提出了一些改良的措施和方法。     

甘薯遗传转化及其在分子育种中的应用

甘薯是全球重要的块根类作物,不仅为人类提供了粮食,同时也是动物饲料、淀粉及燃料乙醇等工业加工的原材料。建立甘薯遗传转化体系不仅是开展甘薯重要基因功能验证的平台,同时也是甘薯转基因分子育种的必要手段。本文对甘薯遗传转化技术的发展及应用进行了综述。     

Agrobacterium-Mediated Plant Transformation: the Biology behind the “Gene-Jockeying” Tool

Agrobacterium tumefaciens and related Agrobacterium species have been known as plant pathogens since the beginning of the 20th century. However, only in the past two decades has the ability of Agrobacterium to transfer DNA to plant cells been harnessed for the purposes of plant genetic engineering. Since the initial reports in the early 1980s using Agrobacterium to generate transgenic plants, scientists have attempted to improve this “natural genetic engineer” for biotechnology purposes. Some of these modifications have resulted in extending the host range of the bacterium to economically important crop species. However, in most instances, major improvements involved alterations in plant tissue culture transformation and regeneration conditions rather than manipulation of bacterial or host genes. Agrobacterium-mediated plant transformation is a highly complex and evolved process involving genetic determinants of both the bacterium and the host plant cell. In this article, I review some of the basic biology concerned with Agrobacterium-mediated genetic transformation. Knowledge of fundamental biological principles embracing both the host and the pathogen have been and will continue to be key to extending the utility of Agrobacterium for genetic engineering purposes.     

质体基因工程中选择标记基因研究进展

与细胞核基因工程相比,质体基因工程能更安全、精确和高效地对外源基因进行表达,作为下一代转基因技术已广泛用于基础研究和生物技术应用领域。与细胞核基因工程一样,质体基因工程中也需要合适的选择标记基因用于转化子的筛选和同质化,但基于质体基因组的多拷贝性和母系遗传特点,转化子的同质化需要一个长期的筛选过程,这就决定了质体基因工程中选择标记基因的选择标准将不同于细胞核基因工程中广泛使用的现行标准。目前,质体基因工程的遗传转化操作中使用较多的是抗生素选择标记基因,出于安全性考虑,需要找到可替换、安全的选择标记基因或有效的标记基因删除方法。本文在对质体基因工程研究的相关文献分析基础之上,对主要使用的选择标记基因及其删除体系进行了综述,并对比了其优缺点,同时探讨了质体基因工程中所使用的报告基因,以期为现有选择标记基因及其删除体系的改进和开发提供一定参考,进一步推动质体基因工程,尤其是单子叶植物质体基因工程的发展。     

Biotechnological advances in guava (Psidium guajava L.): recent developments and prospects for further research

Guava (Psidium guajava L.), an important fruit crop of several tropical and sub-tropical countries, is facing several agronomic and horticultural problems such as susceptibility to many pathogens, particularly guava wilting caused by Fusarium oxysporium psidii, low fruit growth, short shelf life of fruits, high seed content, and stress sensitivity. Conventional breeding techniques have limited scope in improvement of guava owing to long juvenile period, self incompatibility, and heterozygous nature. Conventional propagation methods, i.e., cutting, grafting or stool layering, for improvement of guava already exist, but the long juvenile period has made them time consuming and cumbersome. Several biotechnological approaches such as genetic transformation may be effective practical solutions for such problems and improvement of guava. The improvement of fruit trees through genetic transformation requires an efficient regeneration system. During the past 2–3 decades, different approaches have been made for in vitro propagation of guava. An overview on the in vitro regeneration of guava via organogenesis, somatic embryogenesis, and synthetic seeds is presented. Organogenesis in several different genotypes through various explant selection from mature tree and seedling plants has been achieved. Factors affecting somatic embryogenesis in guava have been reviewed. Production of synthetic seeds using embryogenic propagules, i.e., somatic embryos and non-embryogenic vegetative propagules, i.e., shoot tips and nodal segments have also been achieved. Development of synthetic seed in guava may be applicable for propagation, short-term storage, and germplasm exchange, and distribution. An initial attempt for genetic transformation has also been reported. The purpose of this review is to focus upon the current information on in vitro propagation and biotechnological advances made in guava.     

New Genes for Old Trees

In addition to the extensive improvement programmes within fruitorchards and forest stands, considerable momentum is being generatedin the application of genetic manipulation strategies to a varietyof woody species. Several transformation approaches have beenadopted for the production of transgenic trees. These includeAgrobacterium-mediated gene delivery, chemical and/or electricalstimulated uptake of DNA into protoplasts, and the use of thenewer technology of high velocity bombardment of plant tissueswith DNA-coated particles. Transformation offers advantagesover other genetic manipulation techniques, such as somatichybridization, in that it allows the directed improvement oftrees with minimum disruption of the genetic integrity of anelite genome. The information presented here is a comprehensivereview of transformation in woody plants. Many of the advanceshave been made in this area during the last five years. Key words: Woody species, transformation, Agrobacterium, direct gene transfer