根癌农杆菌转化禾谷类作物及影响其转化的因素

综述了根癌农杆菌转化禾谷类作物的研究现状,根癌农杆菌与禾谷类作物间的相互作用研究,根癌农杆菌成功转化禾谷类的例子;影响根癌农杆菌转化成功的因素,如菌株类型,感受态细胞的选择,Vir基因的活化,选择合适的转化途径等。这些将为利用根癌农杆菌介导的方法,将外源基因导入禾谷类作物提供有益的帮助。     

影响根癌农杆菌附着禾谷类作物培养细胞的因素

本研究利用水稻、小麦、玉米等主要禾谷类作物悬浮培养细胞,观察农杆菌对禾谷类作物培养细胞的附着,实验结果表明:植物细胞的生理状态和分化发育进程对农杆菌的附着有明显的影响;通过对农杆菌的Vir 区基因进行预活化诱导处理,能显著提高其在禾谷类作物培养细胞上的附着,胭脂碱型农杆菌C 58 C 1(pMP 90+pBI 121)预处理后增加附着的效果较章鱼碱型农杆菌LBA 4404(pAL 4404+pBI121)更显著些。此外,在改善共培养环境条件下(如添加对农杆菌表现强烈趋化性的精氨酸和施行抽气减压处理),农杆菌能大量附着在经过果胶酶预处理的禾谷类作物悬浮培奍细胞上。     

影响根癌农杆菌介导水稻转化的因素分析

根癌农杆菌与来自水稻成熟种子盾片的愈伤组织共培养,将GUS基因导入水稻愈伤组织,并获得了转基因植株。通过比较影响根癌农杆菌转化频率的各种因素,表明激素配比为2,4-D1mg/L、TDZ0.5mg/L、NAA1mg/L时,可以大大促进籼稻愈伤组织的分化能力;酚类化合物的加入使农杆菌的转化频率提高8.9%-23.5%;共培养时农杆菌的稀释方式及适当调整潮霉素（hygB）的使用浓度影响到农杆菌的转化频率。     

根癌农杆菌在丝状真菌转化中的应用

原生质体转化法是丝状真菌转化的传统方法,但其过程繁琐且转化效率低。根癌农杆菌介导的转化方法原本是进行植物遗传转化的标准方法,但近年来发现该方法还可用于丝状真菌的转化。根癌农杆菌介导的丝状真菌转化具有操作简便、转化效率高、重复性好等优点,从而可以解决丝状真菌转化难的问题。在本文中,就其转化机制、特点和转化条件优化等方面的最新研究进展进行了综述。     

影响根癌农杆菌介导的木霉菌遗传转化因素分析

采用根癌农杆菌介导的转化方法,以木霉菌分生孢子为受体材料,对影响转化效率的主要因素进行了分析。结果表明,农杆菌菌株类型、初始菌液量、分生孢子浓度、共培养时间以及乙酰丁香酮的诱导等因素对转化效率都具有重要的影响。通过对这些因素的分析,基本得出了根癌农杆菌转化系统对木霉菌遗传转化的特点和规律,为将该转化系统用于其它丝状真菌的遗传转化提供了重要参考。     

根癌农杆菌介导的水稻高效转化系统的建立

比较了影响根癌农杆菌转化水稻的各种因素后,建立了农杆菌介导的水稻高效转基因实验体系。按该体系,水稻品种中花１１号预培养４ｄ的幼胚经农杆菌ＥＨＡ１０５／ｐＣＡＭＢＩＡ１３０１感染后,具有ＧＵＳ基因瞬间表达的幼胚比例在５０％以上,最高可达９０％,按产生潮霉素抗性愈伤和转基因植株的比例计算,转化率分别达到了８７．６％和６４．６％。     

根癌农杆菌介导库拉索芦荟遗传转化因素优化

以美国库拉索芦荟的横切薄片(transversethincelllayer,tTCL)作为转化外植体,初步研究了以根癌 农杆菌介导的多种因子对芦荟遗传转化的影响。结果表明:菌株EHA105比LBA4404及AGL1转化率高; 除了乙酰丁香酮(acetosyringone)外,菌液的预处理和重悬液的pH值也是影响转化的主要因子;菌液的预处 理和适合的蔗糖浓度对转化也有促进作用;感染时间为12～18min,共培养的温度和时间分别以25℃及5d 为佳。     

根癌农杆菌转化紫草的研究

紫草 (ＬｉｔｈｏｓｐｅｒｍｕｍｅｒｙｔｈｒｏｒｈｉｚｏｎＳｉｅｂ .ｅｔＺｕｃｃ)是传统中药。其根部含有萘醌类化合物—紫草素及其衍生物 ,具有显著的抗菌、抗炎、抗癌以及促进伤口愈合等生理活性。紫草素同时也是一种名贵化妆品染料。科学家对紫草的研究兴趣是基于其资源的缺乏及紫草植物本身所具有的一些特点 ;如 :紫草素及其衍生物的颜色特性可凭借肉眼观察 ,紫草素及其衍生物只在紫草的根部积累 ,紫草素合成的次生代谢途径受多种酶和外界条件 (光照 ,营养等 )的调节等。紫草细胞培养 (Ｆｕｊｉｔａ等 ,1983;叶和春等 ,1991)可以产…     

根癌农杆菌转化植物的细胞学及分子生物学概论

植物冠瘦瘤是由根癌农杆菌诱发产生的。致瘤的 遗传信息贮存在根癌农杆菌的肿瘤诱导质校- Ti质 粒上,冠瘦瘤的产生是Ti质粒T区DNA整合进植 物细胞染色体并表达的结果。     

农杆菌vir基因诱导因子研究进展

在众多遗传转化法中,农杆菌(Agrobacterium tumefaciens)介导法以易操作、低费用、插入片段明确、拷贝数低等独特优点成为植物遗传转化的首选。然而,至今仍有许多物种不能被农杆菌转化。研究表明,农杆菌的转化能力是由位于染色体基因组之外Ti质粒上的vir基因决定的。在所有vir基因中,除virA和virG组成型表达外,其它vir基因的表达均需酚类化合物的诱导;糖类物质可增强酚类化合物对vir基因的诱导;低磷酸和酸性pH环境也可促进vir基因的诱导表达。文章论述了酚类化合物、糖类物质、低磷酸、酸性pH和培养温度等因素对农杆菌vir基因诱导表达的影响,以期为更好地利用这一天然载体及为提高转化效率提供依据。     

根癌农杆菌转化条件优化的研究

目的:确立一个快速高效转化根癌农杆菌的实验方案。方法:以pCAMBIA1305.1质粒作为外源DNA转化农杆菌GV3101。通过对GV3101生长状态的测定,并对重悬液的种类和浓度、速冻时间、热处理温度等条件逐一进行筛选,以确定最适合GV3101转化的实验条件。结果:以TSS缓冲液重悬细胞,液氮速冻3min后于28℃热处理5min,农杆菌转化效率可达到105。结论:改进的转化方法转化率高,重复性好,简单易行,为用农杆菌介导法进行植物遗传转化的第一个限速步骤提供了很好的解决方案。     

Factors influencing Agrobacterium tumefaciens-mediated transformation of Artemisia annua L.

Following our previously described Agrobacterium tumefaciens-mediated transformation procedure for Artemisia annua L., we have undertaken several additional experiments to establish the importance of some parameters such as explant type, age of explant source, A. tumefaciens strain and type of binary vector. Several binary vectors were useful for the production of transgenic callus on explants of different ages. In transformed calli, a good correlation between integration and expression of foreign DNA was observed: different assays showed expression of β-Glucuronidase, neomycin phosphotransferase II, superoxide dismutase and bleomycin acetyl transferase. The regeneration of transgenic plants required more restricted conditions. Only with the pTJK136 vector could transgenic plants be obtained from leaf and stem explants from 12- to 18-week-old plants. Co-cultivation for 48 h seemed favorable for the regeneration of transgenic plants. Stable integration and expression of the transgenes was also shown in the progeny. Received: 18 August 1997 / Revision received: 3 December 1997 / Accepted: 3 July 1998     

高效、快速地将外源DNA导入根癌土壤杆菌

室温下用50mmol/LCaCl_2处理根癌土壤杆菌(Agrobacterium tumefaciens)以制备感受态细胞,然后经0℃冰浴及28℃热击处理,成功地将Ti质粒中间载体(>10kb)导入了根癌土壤农杆菌中。转化效率每个活细胞可达10~(-4)～10~(-5)转化子或10~6转化子/μgDNA。探讨了该菌细胞生长状态、CaCl_2滚滚浓度、温度、液氮、热击、复苏时间以及感受态细胞于4℃或—20℃(加15％甘油)下保存时间对根癌土壤杆菌转化的影响。     

根癌农杆菌介导的草莓遗传转化研究进展

随着植物离体再生技术的日益成熟和多种外源目的基因的分离与克隆,转基因技术以目的性强、周期短等优点成为草莓品种改良的重要途径。在草莓上采用的遗传转化方法主要是农杆菌介导法。概述了农杆菌介导法的转化机理以及基因型、农杆菌菌株、侵染时间和菌液浓度、共培养时间、酚类物质等对草莓遗传转化的影响,并从草莓果实贮藏保鲜、抗除草剂、抗病毒、抗虫、抗真菌、转基因疫苗等方面对近年来草莓的转基因研究进展进行了总结。     

Transformation of rice mediated by Agrobacterium tumefaciens

Agrobacterium tumefaciens has been routinely utilized in gene transfer to dicotyledonous plants, but monocotyledonous plants including important cereals were thought to be recalcitrant to this technology as they were outside the host range of crown gall. Various challenges to infect monocotyledons including rice with Agrobacterium had been made in many laboratories, but the results were not conclusive until recently. Efficient transformation protocols mediated by Agrobacterium were reported for rice in 1994 and 1996. A key point in the protocols was the fact that tissues consisting of actively dividing, embryonic cells, such as immature embryos and calli induced from scutella, were co-cultivated with Agrobacterium in the presence of acetosyringonc, which is a potent inducer of the virulence genes. It is now clear that Agrobacterium is capable of transferring DNA to monocotyledons if tissues containing competent cells are infected. The studies of transformation of rice suggested that numerous factors including genotype of plants, types and ages of tissues inoculated, kind of vectors, strains of Agrobacterium, selection marker genes and selective agents, and various conditions of tissue culture, are of critical importance. Advantages of the Agrobacterium-mediated transformation in rice, like on dicotyledons, include the transfer of pieces of DNA with defined ends with minimal rearrangements, the transfer of relatively large segments of DNA, the integration of small numbers of copies of genes into plant chromosomes, and high quality and fertility of transgenic plants. Delivery of foreign DNA to rice plants via A. tumefaciens is a routine technique in a growing number of laboratories. This technique will allow the genetic improvement of diverse varieties of rice, as well as studies of many aspects of the molecular biology of rice.     

根癌农杆菌介导的大豆遗传转化

农杆菌介导法是大豆遗传转化的重要方法之一 ,许多实验室应用该方法得到了转基因大豆 ,但目前使用该方法进行转化的效率还比较低 ,尚需深入研究。农杆菌菌株、大豆基因型、组织培养条件、T-DNA的转移效率和转化后的筛选模式都会影响大豆转化的效率。概述了近年来根癌农杆菌介导的大豆遗传转化的一些重要成果 ,以及转化过程中大豆的易感性与农杆菌的转化能力、乙酰丁香酮促进vir基因活化、转化的受体系统和巯基混合物减轻受体材料的褐化、提高T DNA的转移效率等几个重要因素的研究进展 ,并介绍了转化中常用的几个筛选标记基因 (nptⅡ、hpt、bar基因和突变的ahas基因 )及通过共转化法去除标记基因的方法 ,同时对今后研究的重点进行了讨论.     

Development of a binary vector system for plant transformation based on the supervirulent Agrobacterium tumefaciens strain Chry5

This report describes the disarming of Agrobacterium tumefaciens Chry5, a strain highly tumorigenic on soybean. Disarming was achieved by removing an approximately 16.5-kb segment of the 285-kb Ti plasmid pTiChry5, including approximately 4 kb of the oncogenic T-DNA and an extended region right of the T-DNA, and replacing it with a gene for carbenicillin resistance, through homologous recombination. The deletion was confirmed with Southern analysis, and the loss of tumorigenicity was verified in tobacco and tomato plant stem inoculation assays. The deletion mutant, named KYRT1, successfully transferred the β-glucuronidase (GUS) gene into tobacco leaf tissue, producing GUS-expressing callus which could be regenerated into viable plants. In a comparative study, the transformation efficiency of A. tumefaciens KYRT1, GV3850, and EHA105 was assayed by inoculating cotyledonary node explants. The results of this study revealed that, in a binary vector system, KYRT1 is equally or more effective than EHA105 or GV3850 at delivering DNA into soybean. Received: 30 January 1997 / Revision received: 10 June 1997 / Accepted: 5 July 1997     

根癌农杆菌介导的木霉遗传转化及应用进展

木霉作为土传植物病原菌的生防真菌,研究其功能基因具有重要的意义。根癌农杆菌介导的遗传转化(ATMT)为木霉功能基因的研究提供了一个强有力的工具。对根癌农杆菌介导木霉遗传转化的机理、特点、方法及其在木霉中的应用进行了综述。