辣椒高效再生体系及抗病基因工程研究进展

通过外源基因的转入来提高辣椒抗病越来越受关注,而辣椒高效遗传转化再生体系的建立是充分利用转基因技术的首要步骤。本文从辣椒再生和遗传转化体系的优化及抗病基因工程等方面的国内外研究进展进行综述,为今后辣椒转基因研究提供一定的参考依据。     

大豆遗传转化技术在转基因大豆研究中的应用

大豆是公认的难转化的作物,大豆的遗传转化还没有模式化。利用转基因技术的原理和方法,对大豆遗传体系进行优化,可以实现对大豆产量和品质的改良。综述了应用于大豆遗传转化的研究方法,浅谈转基因技术的重要性,对转基因发展方向进行了展望。现阶段大豆遗传转化的效率依旧偏低,无法形成规模化的转基因体系。因此,建立高效、快速、稳定的大豆组织培养再生体系,解决外源基因难导入的难题,使之广泛应用于大豆生产成为亟待解决的问题。     

植物遗传转化新技术和新方法

目前通过遗传转化技术获得了许多植物的转基因植株,一些重要农作物转基因新品种已进入产业化阶段,展现出极好的应用前景。但随着研究的不断深入,在如何提高遗传转化效率和转基因安全性等方面,一些新的技术和方法不断出现并得到应用,如胚状体再生系统、叶绿体转化系统、超声波辅助农杆菌介导法、位点特异重组MATvector系统、正选择系统以及新的转基因分子检测方法,使遗传转化技术向高效、安全方向发展,新一代的转基因植物也将会更适应人们和生态环境的需求。     

‘神马’菊花DREB1A基因的分离及同源遗传转化

逆境诱导转录因子DREB1A基因在植物中的超量表达能够提高植株对低温、干旱、盐渍、高温等非生物胁迫的耐性。从菊花中克隆得到DgDREB1A基因,构建了转基因表达载体pBIG-DREB1A,并转入农杆菌LBA4404中;在建立了菊花高效再生体系的基础上,优化受体再生体系,通过根癌农杆菌介导将DgDREB1A基因转入切花菊‘神马’品种。PCR结果显示,在获得的38株卡那霉素抗性植株中有8株为阳性,表明外源基因已整合到转化植株基因组中,转化效率为3‰。本研究为培育综合抗逆性良好的菊花新品种奠定工作基础。     

84K杨愈伤组织再生体系和直接分化再生体系遗传转化的比较性研究

植物转基因必须以建立良好的植物转化受体系统为基础,而良好的受体系统必须以具有高频率的转化率及较强的再生能力为前提。实验以84K杨叶片为材料研究其在不同培养条件、不同种类及浓度的植物激素对其脱分化及再分化的影响,并建立了两种成熟的组织再生系统,得出组织培养体系与遗传转化体系的受体系统在激素配比方面存在一定差距,所以在此基础上进行了PCK1、PCK2两个基因的愈伤途径和不定芽途径途径的遗传转化,并对两种遗传转化体系进行了对比性分析并总结出两种体系的优缺点。     

基因枪转化小麦主要影响因素细述

基因枪转化是目前小麦遗传转化的主要技术之一,高效的基因枪转化系统对于转基因小麦新品种培育、候选基因功能鉴定和功能基因组学研究具有重要意义。本文综述了影响基因枪转化小麦效率的主要因素,包括基因型、外植体、植物生长调节剂、轰击参数、筛选体系等,以期为进一步改进小麦基因枪转化技术,提高基因枪转化小麦的效率提供参考。     

高粱遗传转化研究进展

高粱是世界上仅次于小麦、水稻、玉米和大豆的重要作物之一,然而由于其高效、稳定的遗传转化体系的建立较难,限制了其转基因研究进程.近年来,随着转基因技术的不断发展和完善,高粱转基因研究也取得了飞速的发展.从高粱遗传转化再生系统中外植体的选择、转化方法、影响转化和基因表达效率的因素等几方面进行了综述,并总结转基因高粱研究进展.     

负压处理对农杆菌介导小麦成熟胚转化效率的影响

目的:提高小麦成熟胚遗传转化效率,为建立快速高效的小麦成熟胚遗传转化体系奠定基础.方法:以普通小麦HB341、SN2618、TS021和栽培二粒小麦成熟种子为试材,采用整粒切胚诱愈的方法,通过农杆菌GV3101/pBI121::gus介导,研究负压处理对小麦成熟胚遗传转化的影响.结果:接种侵染过程中的负压处理,对小麦成熟胚愈伤组织的诱导没有显著影响,但对小麦成熟胚的遗传转化却有显著性影响.负压处理10、20、30次,转化率分别较对照组提高了9.37倍、10.90倍和10.03倍,最高转化率可达12.50%.同时负压处理能够提高小麦成熟胚转化效率,具有普遍意义.结论:该研究为快速高效小麦成熟胚转化体系的建立提供了依据.     

普通小麦品种Alondra＇s遗传转化体系的建立

小麦（Triticum aestivum）幼胚愈伤组织的诱导和分化再生有高度依赖基因型特征。为了建立和优化Alondra’s的高效再生及遗传转化体系,为小麦遗传转化提供更多的受体基因型,以Alondra’s的幼胚为外植体,研究了培养基种类、不同激素配比等对其幼胚愈伤组织诱导及再生的影响。结果表明,在使用N6培养基时,添加3mg·L^-1的2,4-D并附加1000mg·L^-1的CH对愈伤组织的诱导效果较好;添加4mg·L^-1的ZT、不附加IAA对愈伤组织的分化效果最好。通过构建植物表达载体pCAMBIA1301-220.6,利用基因枪法将HYG基因导入Alondra’s幼胚愈伤组织中,以建立Alondra’s的高效遗传转化体系。结果在含100mg·L^-1潮霉素的选择培养基上进行筛选、分化,获得了30棵抗性植株。经PCR检测,其中5株为阳性转基因植株,转化率为0.5%。Alondra＇s遗传转化体系的建立丰富了小麦遗传转化的基因型,为小麦品种的转基因改良和在不同背景下研究基因的功能奠定了良好的基础。     

丹参遗传转化体系建立及应用研究进展

丹参(Salvia miltiorrhiza Bunge)是我国一种传统的大宗中药材,主要活性成分丹参酮和丹酚酸被广泛用于治疗心脑血管等疾病。建立高效、稳定的遗传转化体系,对丹参进行定向改良,为丹参酮和丹酚酸类成分工业化生产及丹参药材产量与质量提高提供了可能。本文结合国内外的研究,对丹参遗传转化方法进行了系统总结,从外植体、培养基、菌液浓度等影响丹参遗传转化因素方面进行综述。对近5年丹参遗传转化研究的关键酶基因和转录因子进行归纳,并对未来的研究重点进行了展望。     

An efficient protocol for Agrobacterium-mediated genetic transformation of Antirrhinum majus

Snapdragon (Antirrhinum majus L.) is a popular ornamental and model plant species, and the recently released reference genome could greatly boost its utilization in fundamental research. However, the lack of an efficient genetic transformation system is still a major limiting factor for its full application in genetic and molecular studies. In this study, a simple method for quick regeneration and efficient Agrobacterium-mediated transformation of snapdragon was developed. Cotyledon petiole and hypocotyl explants derived from two-week-old seedlings were cultured on MS media supplemented with 2 mg/L zeatin (ZT), 0.2 mg/L 1-naphthaleneacetic acid (NAA), and 2 mg/L AgNO₃, and adventitious shoots were regenerated through organogenesis with an average regeneration of 48.00% and 41.33%, respectively. By contrast, the regeneration frequency was only 22.67% for cotyledon petiole and 25.67% for hypocotyl explants in the absence of AgNO₃. Moreover, the application of AgNO₃ promoted indirect shoot organogenesis, while direct shoot organogenesis occurred in the absence of AgNO₃ from both hypocotyl or cotyledon petiole explants. Agrobacterium-mediated genetic transformation systems were developed with this high-efficient regeneration system. The transformation efficiency has been improved from 0 to 1% through the direct shoot organogenesis to 3 to 4% via the indirect shoot organogenesis. This efficient regeneration and genetic transformation method could be important for future use of snapdragon as a model plant to address some fundamental questions which are hard to be solved by using other model plant species, and to accelerate the breeding process through CRISPR/Cas9 genome editing.

     

The molecular path to in vitro shoot regeneration

Plant regeneration through de novo shoot organogenesis in tissue culture is a critical step in most plant transformation and micropropagation procedures. Establishing an efficient regeneration protocol is an empirical process and requires optimization of multiple factors that influence the regeneration capacity. Here, we review the molecular process of shoot induction in a two-step regeneration protocol and focus on the role of auxins and cytokinins. First, during incubation on an auxin-rich callus induction medium (CIM), organogenic callus is produced that exhibits characteristics of a root meristem. Subsequent incubation on a cytokinin-rich shoot induction medium (SIM) induces root to shoot conversion. Through a detailed analysis of the different aspects of shoot regeneration, we try to reveal hinge points and novel candidate genes that may be targeted to increase shoot regeneration capacity in order to improve transformation protocols.     

Common regulatory themes in meristem development and whole-plant homeostasis

The maintenance of meristems throughout plant ontogeny allows the development of a diversity of structural forms from the same genetic base. Examination of the common and contrasting features of these meristems leads to the outline of common regulatory themes in meristem development. In particular, by including comparisons with embryogenesis research, we see that hormones and factors that are generally attributed roles in stress response, such as redox potential, carotenoids, flavonoids, brassinosteroids, jasmonic acid and ethylene, are emerging as major candidates for long-distance or short-distance signalling molecules in meristem development. In each case, hormone response appears to be influenced greatly by the developmental window or transition stage at which the meristem resides.     

Novel and potential application of cryopreservation to plant genetic transformation

The world population now is 6.7 billion and is predicted to reach 9 billion by 2050. Such a rapid growing population has tremendously increased the challenge for food security. Obviously, it is impossible for traditional agriculture to ensure the food security, while plant biotechnology offers considerable potential to realize this goal. Over the last 15 years, great benefits have been brought to sustainable agriculture by commercial cultivation of genetically modified (GM) crops. Further development of new GM crops will with no doubt contribute to meeting the requirements for food by the increasing population. The present article provides updated comprehensive information on novel and potential application of cryopreservation to genetic transformation. The major progresses that have been achieved in this subject include (1), long-term storage of a large number of valuable plant genes, which offers a good potential for further development of novel cultivars by genetic transformation; (2), retention of regenerative capacity of embryogenic tissues and protoplasts, which ensures efficient plant regeneration system for genetic transformation; (3), improvement of transformation efficiency and plant regeneration of transformed cells; (4), long-term preservation of transgenic materials with stable expression of transgenes and productive ability of recombinant proteins, which allows transgenic materials to be stored in a safe manner before being analyzed and evaluated, and allows establishment of stable seed stocks for commercial production of homologous proteins. Data provided in this article clearly demonstrate that cryo-technique has an important role to play in the whole chain of genetic transformation. Further studies coupling cryotechnique and genetic transformation are expected to significantly improve development of new GM crops.     

Genome scale transcriptome analysis of shoot organogenesis in Populus

Background  

Our aim is to improve knowledge of gene regulatory circuits important to dedifferentiation, redifferentiation, and adventitious meristem organization during in vitro regeneration of plants. Regeneration of transgenic cells remains a major obstacle to research and commercial deployment of most taxa of transgenic plants, and woody species are particularly recalcitrant. The model woody species Populus, due to its genome sequence and amenability to in vitro manipulation, is an excellent species for study in this area. The genes recognized may help to guide the development of new tools for improving the efficiency of plant regeneration and transformation.     

荔枝和龙眼遗传转化体系研究进展(综述)

综述近年来利用荔枝、龙眼不同品种和类型的外植体进行组织培养及植株再生取得的新成果,同时对建立荔枝、龙眼遗传转化体系的研究新进展进行了报道,并对其研究前景作以分析及展望。     

Development of efficient catharanthus roseus regeneration and transformation system using agrobacterium tumefaciens and hypocotyls as explants

ABSTRACT: BACKGROUND: As a valuable medicinal plant, Madagascar periwinkle (Catharanthus roseus) produces many terpenoid indole alkaloids (TIAs), such as vindoline, ajamlicine, serpentine, catharanthine, vinblastine and vincristine et al. Some of them are important components of drugs treating cancer and hypertension. However, the yields of these TIAs are low in wild-type plants, and the total chemical synthesis is impractical in large scale due to high-cost and their complicated structures. The recent development of metabolic engineering strategy offers a promising solution. In order to improve the production of TIAs in C. roseus the establishment of an efficient genetic transformation method is required. RESULTS: To develop a genetic transformation method for C. roseus, A. tumefaciens strain EHA105 was employed which harbors a binary vector pCAMBIA2301 containing a report beta-glucuronidase (GUS) gene and a selectable marker neomycin phosphotransferase II gene (NTPII). The influential factors were investigated systematically and the optimal transformation condition was achieved using hypocotyls as explants, including the sonication treatment of 10 min with 80 W, A. tumefaciens infection of 30 min and co-cultivation of 2 d in 1/2 MS medium containing 100 muM acetosyringone. With a series of selection in callus, shoot and root inducing kanamycin-containing resistance mediums, we successfully obtained stable transgenic regeneration plants. The expression of GUS gene was confirmed by histochemistry, polymerase chain reaction, and genomic southern blot analysis. To prove the efficiency of the established genetic transformation system, the rate-limiting gene in TIAs biosynthetic pathway, DAT, which encodes deacetylvindoline-4-O-acetyltransferase, was transferred into C. roseus using this established system and 9 independent transgenic plants were obtained. The results of metabolite analysis using high performance liquid chromatography (HPLC) showed that overexpression of DAT increased the yield of vindoline in transgenic plants. CONCLUSIONS: In the present study, we report an efficient Agrobacterium-mediated transformation system for C. roseus plants with 11.11 % of transformation frequency. To our knowledge, this is the first report on the establishment of A. tumefaciens mediated transformation and regeneration of C. roseus. More importantly, the C. roseus transformation system developed in this work was confirmed in the successful transformation of C. roseus using a key gene involved in TIAs biosynthetic pathway resulting in the higher accumulation of vindoline in transgenic plants.     

根癌农杆菌介导的黄瓜转基因研究进展

黄瓜Cucumis sativus是世界性的重要蔬菜作物。农杆菌介导的转基因技术是研究植物基因功能及品种改良的重要手段。为进一步加快黄瓜的转基因研究和育种进程,文中针对农杆菌介导的黄瓜遗传转化方法,从黄瓜再生能力的影响因素、遗传转化条件和过程中各类添加物质等方面,阐述了根癌农杆菌介导的黄瓜转基因研究进展及存在的问题,并对提高黄瓜遗传转化效率和安全筛选标记的应用等前景进行了展望,以期为黄瓜抗逆育种和果实品质改良等研究提供参考。     

Genetic transformation technology: Status and problems

Summary Transfer of genes from heterologous species provides the means of selectively introducing new traits into crop plants and expanding the gene pool beyond what has been available to traditional breeding systems. With the recent advances in genetic engineering of plants, it is now feasible to introduce into crop plants, genes that have previously been inaccessible to the conventional plant breeder, or which did not exist in the crop of interest. This holds a tremendous potential for the genetic enhancement of important food crops. However, the availability of efficient transformation methods to introduce foreign DNA can be a substantial barrier to the application of recombinant DNA methods in some crop plants. Despite significant advances over the past decades, development of efficient transformation methods can take many years of painstaking research. The major components for the development of transgenic plants include the development of reliable tissue culture regeneration systems, preparation of gene constructs and efficient transformation techniques for the introduction of genes into the crop plants, recovery and multiplication of transgenic plants, molecular and genetic characterization of transgenic plants for stable and efficient gene expression, transfer of genes to elite cultivars by conventional breeding methods if required, and the evaluation of transgenic plants for their effectiveness in alleviating the biotic and abiotic stresses without being an environmental biohazard. Amongst these, protocols for the introduction of genes, including the efficient regeneration of shoots in tissue cultures, and transformation methods can be major bottlenecks to the application of genetic transformation technology. Some of the key constraints in transformation procedures and possible solutions for safe development and deployment of transgenic plants for crop improvement are discussed.