简单高效的根癌农杆菌介导的水稻基因转化方法

本文在研究影响农杆菌介导的水稻转化的主要因素基础上,建立了一套简单、高效的水稻转基因系统。将水稻成熟胚来源的愈伤组织用农杆菌EHA101/pHQ9,EHA 101/pHQ 10,EHA 101/pHQ T3感染后,筛选抗性愈伤,经分化获得转化株。抗性愈伤的平均得率为约100个愈伤/g愈伤外植体,抗性愈伤的分化频率平均高达85%。转基因植株的GUS染色、Southern杂交结果表明,T-DNA上的外源基因已整合进转基因植物的基因组中。转基因植株T1代对潮霉素的抗性表明,多数转基因株系符合孟德尔分离比3∶1。该系统的建立将有助于应用T-DNA标签法和基因打靶法进行水稻功能基因组的研究。     

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％。     

根癌农杆菌介导的水稻遗传转化

就根癌农杆菌介导水稻遗传转化的研究历程和影响农杆菌转化水稻的几个关键因素以及这一问题的前景作了评述和展望     

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87．6％和64．6％。转基因植株总DNA的Southern杂交分析表明T－DNA上的外源基因已整合进了水稻基因组,且在大多数转基因植株中表现为单拷贝插入;遗传分析证明T1代的表型分离符合孟德尔法则。此转化系统的建立为高效地将有用的外源DNA导入水稻植株奠定了基础。     

根癌农杆菌介导Bt基因转化水稻的研究

为了培育出无筛选标记基因的转基因水稻,试验将loxp-hpt-loxp基因与成基因连锁在-起转化水稻方法,得到loxp-hpt—loxp—Bt转基因水稻植株,再与同质的带有ere基因的水稻杂交,以定向删除潮霉素抗性筛选标记。试验表明以水稻品种“皖粳97”为供试材料,将成熟胚来源的愈伤组织用根癌农杆菌EHA105／pCAMBIA1305．1感染后,筛选出抗性愈伤组织并获得再生植株。经PCR验证,得到20棵转基因水稻植株。     

根癌土壤杆菌介导的水稻高效转化和转基因植株的高频再生

利用根襄封杆菌（Ａｇｒｏｂａｃｔｅｒｕｍ ｔｕｍｅｆａｃｉｅｎｓ（Ｓｍｉｔｈ ｅｔ Ｔｏｗｎｓｅｎｄ）Ｃｏｎｎ）介导的转化方法对４个粳稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．ｓｓｐ．ｊａｐｏｎｉｃａ）品种和２个灿稻（Ｏ．ｓａｔｉｖａ ｓｓｐ．ｉｎｄｉｃａ）品种进行了转化。在对影响根癌土壤杆菌转化水稻效率的多种因素进行比较研究后,建立了根癌土壤杆菌介导的水稻高效转化和再生系统。将水稻成熟胚和未成熟胚来源的     

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。     

根癌农杆菌介导的水稻转化研究进展

农杆菌介导的水稻基因转化是水稻基因转化的热门。本文对由农杆菌介导转化获得的水稻品系（品种）,影响农杆菌介导转化的因素,农村菌浸染的方法,外源基因的检测和遗传等方面作综合论述,并提出了农杆菌介导转化水稻的前景。     

根癌农杆菌介导的水稻转基因技术体系的优化

对根癌农杆菌介导水稻遗传转化的各重要因素逐一分析,比较不同基因型、培养基成份、光照、继代次数、菌液浓度、侵染时间、干燥情况等因素对遗传转化的影响。通过培养条件的优化,建立了一个高效的水稻转化技术体系。研究结果表明,相比较于暗培养,光照培养进行愈伤诱导可以使诱导天数缩短4~5d;诱导培养基中加入适量的激素可以使籼稻愈伤诱导提高25%~30%;分化培养基中加入适量的氨基酸和甘露醇可以使植株再生频率提高15%~20%。     

根癌农杆菌介导转化诸葛莱获得转基因植株

以诸葛莱下胚轴和子叶为材料,在附加ＢＡ和ＮＡＡ的ＭＳ培养在上诱导芽于生,在１／２ＭＳ培养基上诱导生根,获得完整再生植株,建立了诸葛菜组织培养高频再生体系,再用根癌农杆菌介地转化炒下胚了叶,在附加一定量的氨邪说青霉素,头孢霉和卡那霉素的相应增减基上进行筛选,并增减再生成苗,获得完整抗性再生植株,移植到盛有土壤的花盆中均可存活,生长正常,将再生植株叶片,进行ＧＵＳ、ＮＰＴⅡ酶活性性测定和Ｓｏｕｔｂｅｒ     

A highly efficient in vitro plant regeneration system and Agrobacterium-mediated transformation in Plumbago zeylanica

Plumbago zeylanica is a unique model for studying flowering plant gametogenesis, heterospermy, and preferential fertilization, yet understanding the control of related molecular mechanisms is impossible without efficient and reproducible regeneration and stable genetic transformation. We found three key factors for enhancing successful regeneration: (1) tissue source of explants, (2) combination and concentration of growth regulators, and (3) culture conditions. The highest frequency of shoot regeneration was achieved using hypocotyl segments cultured on MS basal medium supplemented with BA 2.0 mg/l, NAA 0.75 mg/l, adenine 50 mg/l and 10% (v/v) coconut milk under subdued light at 25±2°C; under these conditions, each hypocotyl segment produced over 30 shoots, arising primarily through direct organogenesis after 3 weeks of culture. Regenerated shoots rooted easily on half-strength basal MS medium and were successfully established in the greenhouse. Using this tissue culture protocol, reporter gene GUS under the constitutive CaMV 35S promoter was introduced into P. zeylanica cells of petiole, cotyledon and hypocotyl with A. tumefaciens strains AGL1 and LBA4404. Transient expression was observed in all recipient tissues. Stable transgenic calli originating from petiole were obtained.     

An efficient and universal Agrobacterium-mediated transformation protocol in rice

For development of transgenic varieties of interest in rice, we have developed a simple, efficient and universal Agrobacterium mediated transformation protocol. Mature seeds of two indica (IR64 and Jaya), one each from japonica (AC41039) and aromatic (Basmati370) varieties were used as explants in the present study. Agrobacterium tumefaciens strain EHA 105 carrying Ti plasmid (pBI121) with the selectable marker npt ^II along with the reporter gene uidA encoding ??-glucuronidase (GUS) was successfully integrated with rice genome without use of acetosyringone. Sterile distilled water washing in place of cefotaxime in the elimination process has been used to control excess growth of Agrobacterium. All the material after transformation germinated in 2 to 3?days of co-cultivation on MS basal medium. Germinated seeds transferred to the selection medium i.e. plain MS medium with 50?mg/l of kanamycin, produced two to three primary tillers within 2?weeks. Mesocotyls from 2?week old in vitro grown plants were taken and cultured in the multiplication medium (MS supplemented with 0.5?mg/l BA and 50?mg/l Kanamycin) where within 6?C8?days they produced 3?C4 secondary tillers. All the five to six tiller shoots so produced in the process developed roots on plain MS and grew well when transferred to pots containing autoclaved soil and vermicompost in the proportion of 4:1. Transient expression of GUS was observed in all the tissues of recipient plants. Integration of the transgene was confirmed by employing southern blotting and real-time PCR technique. The transformation protocol developed can be efficiently used across the two major subspecies/ecotypes of the Asian rice cultivar Oryza sativa.     

Establishment of highly efficient and reproducible Agrobacterium-mediated transformation system for tomato (Solanum lycopersicum L.)

In Vitro Cellular & Developmental Biology - Plant - A simple and improved Agrobacterium-mediated transformation protocol of tomato (Solanum lycopersicum) cultivar Rio Grande was developed to...     

A protocol for Agrobacterium-mediated transformation in rice

Agrobacterium-mediated transformation of rice is an important method that has been widely adopted by many laboratories. However, because current approaches rely on culture systems, routine protocols have been established only in japonica rice, especially those varieties with higher regeneration potential. Some very efficient methods have been developed for japonica varieties that enable high-throughput functional analysis in rice; however, many elite japonica, and most indica, varieties are difficult to regenerate, leading to low transformation efficiencies. Much effort has been devoted to improving transformation efficiency for all rice genotypes. Here, we describe an Agrobacterium-mediated rice transformation method that is applicable to easily cultured varieties in addition to elite japonica varieties that are more difficult to culture. Using this method, transgenic rice plants can be obtained in about 2-3 months with a transformation frequency of 30-50%, both in easily cultured varieties and recalcitrant elite japonica rice.     

Agrobacterium-mediated transformation of Javanica rice

Difficulties frequently encountered using direct DNA transfer methods for transformation of Javanica varieties of rice (Oryza sativa L.) have limited the application of biotechnology to these varieties. We now reportAgrobacterium-mediated transformation of Javanica cultivars Gulfmont and Jefferson that are, respectively, widely used or about to enter commercial cultivation in the southern USA. Vigorous, phenotypically normal, fertile plants expressing both the selectable marker and the gene of interest were obtained. Southern analysis showed that only one or two copies of the T-DNA insert were present. Sequence analysis of right border fragments of one line confirmed that insertion was into a coding region of rice nuclear DNA. This analysis also revealed the presence of relatively short regions of permuted T-DNA border sequences, similar to those found afterAgrobacterium-mediated transformation of dicots. Progeny analysis of lines bearing two copies showed co-segregation, indicating that they were located relatively closely on the same chromosome. The introduced genes were transmitted to the R₁ and R₂ generations in a Mendelian fashion, confirming the suitability of this approach for biotechnological improvement of elite rice cultivars.     

Development of an efficient Agrobacterium-mediated transformation system for Brassica carinata

Shoot organogenesis and plant regeneration were readily achieved from cotyledonary petioles and hypocotyls of Brassica carinata. These explants were used for Agrobacterium-mediated transformation. A construct containing the selectable marker genes, neomycin phosphotransferase II, phosphinothricin acetyl transferase and the reporter gene β-glucuronidase, under the control of a tandem 35S promoter, was used for transformation. Although transformation was achieved with both cotyledonary petioles and hypocotyls, cotyledonary petioles responded best, with 30–50% of the explants producing GUS-positive shoots after selection on 25 mg/l kanamycin. Direct selection on L-phosphinothricin also produced resistant shoots but at a lower frequency (1–2%). Received: 9 April 1997 / Revision received: 3 July 1997 / Accepted: 30 July 1997     

A highly efficient electroporation system for transformation of Yersinia

The various pathogenic Yersinia species are not readily and efficiently transformed by classical methods. For this reason, the electroporation technique was applied for genetic transformation of these species. Using optimal conditions, we were able to transform the six Yersinia strains studied with the two most widely used groups of plasmids: pSU2718 (a pACYC184 derivative) and pK19 (a pUC19 derivative). Only Yersinia enterocolitica (Y. e.) serotype 0:8 gave poor results (less than 5 x 10(2) transformants/microgram) DNA). Electrical transformation of the other species resulted in high efficiencies, up to 10(5) transformants/microgram DNA for Y. e. serotypes 0:3 and 0:9, 10(6) for Y. pseudotuberculosis and 10(7) for Y. pestis. The results varied for each strain with the type of plasmid used. Neither the introduced foreign plasmid nor the resident 72-kb virulence plasmid underwent detectable deletions. Transformation was most efficient with supercoiled DNA, decreasing by one and four orders of magnitude for relaxed circular and linearized plasmids, respectively. The ability to easily and efficiently transfer plasmid DNA via electroporation will greatly facilitate the application of recombinant DNA technology for direct cloning and analysis of significant genes into Yersinia.     

A highly efficient electroporation system for transformation of Bacillus licheniformis

Summary Transformation of intact cells of Bacillus licheniformis 5A24 with plasmids pLM6 (2.8 kb), pC194 (2.9 kb) and pCP49 (7.1 kb) by electroporation resulted in 1.5 × 10⁶, 1.2 × 10⁶ , and 5.2 × 10⁴ transformants per μg DNA, respectively. Transformation was possible with plasmid DNA, which was religated after restriction endonuclease digestions. In addition, evidence is presented that indicates that B. licheniformis possesses DNA restriction and modification systems.     

Highly efficient Agrobacterium-mediated transformation of Volvariella volvacea

Agrobacterium tumefaciens-mediated transformation (ATMT) was successfully applied to the edible straw mushroom, Volvariella volvacea. Mycelium pellets were transformed to cold stress resistance using the afp gene as both a selective marker and a reporter gene, under the control of a heterologous Lentinula edodes gpd promoter. The efficiency of transformation is over 100 times higher than that previously reported in V. volvacea. Stable integration of the afp gene with 1-4 copy numbers was confirmed in all 10 randomly selected transgenic events by Southern blot analysis. The mitotic stability of the transformants was demonstrated after five successive transfers on PDA medium without selection pressure and the PCR analysis of basidiospores harvested from transformants.     

An efficient Agrobacterium-mediated transient transformation of Arabidopsis

Agrobacterium tumefaciens-mediated transient transformation has been a useful procedure for characterization of proteins and their functions in plants, including analysis of protein-protein interactions. Agrobacterium-mediated transient transformation of Nicotiana benthamiana by leaf infiltration has been widely used due to its ease and high efficiency. However, in Arabidopsis this procedure has been challenging. Previous studies suggested that this difficulty was caused by plant immune responses triggered by perception of Agrobacterium. Here, we report a simple and robust method for Agrobacterium-mediated transient transformation in Arabidopsis. AvrPto is an effector protein from the bacterial plant pathogen Pseudomonas syringae that suppresses plant immunity by interfering with plant immune receptors. We used transgenic Arabidopsis plants that conditionally express AvrPto under the control of a dexamethasone (DEX)-inducible promoter. When the transgenic plants were pretreated with DEX prior to infection with Agrobacterium carrying a β-glucuronidase (GUS, uidA) gene with an artificial intron and driven by the CaMV 35S promoter, transient GUS expression was dramatically enhanced compared to that in mock-pretreated plants. This transient expression system was successfully applied to analysis of the subcellular localization of a cyan fluorescent protein (CFP) fusion and a protein-protein interaction in Arabidopsis. Our findings enable efficient use of Agrobacterium-mediated transient transformation in Arabidopsis thaliana.