Expression of two insect-resistant genescryIA (b&c)/GNA in transgenic tobacco plants results in added protection against both cotton bollworm and aphids

The synthesizedBacillus thuringiensis insecticidal protein gene cryIA(b&c) and the synthesized geneGNA, (the mannose specific lectin from snowdrop (Galanthus nivalis)), tumefaciens have been inserted into plant expression vector pGW4BAI. Leave stripes ofNicotiana tabacum var. K326 have been transformed withAgrobacterium tumefaciens strain LBA4404 harboring the plant expression vector. 28 kanamycin resistant tobacco plants have been obtained. PCR and Southern blot analyses show that the foreigncryIA andGNA genes have been inserted into the genome of transformed tobacco plants. Haemagglutination assays show thatGNA has a functional activity. Leaf disc bioassays against cotton bollworm (H. armigera) show that the transgenic tobacco plants have a high insecticidal activity. The inhibition of aphid population in leaf disc bioassays againstMyzus persicae shows that the fecundity of aphid on transgenic plants is lower than that on untransformed plants; the aphid population on the transgenic tobacco plants is 25%–70% that on untransformed tobacco plants. ELISA analysis of ClyIA protein in tobcco leaves provides similar data to bioassay results. Through the two bioassays againstH. armigera andM. persicae, several transgenic tobacco plants showing high insect-resistant activities to both pests have been obtained.     

Transgenic tobacco plants harboring tomato proteinase inhibitor II gene and their insect resistance

The plant expression vectors pBCT2 and pBT2 were constructed with the cDNA sequence (tin2) and genomic DNA sequence (tin2i) of tomato proteinase inhibitor II gene respectively. Then the two expression vectors were transferred into tobacco via the Agrobacterium tumefaciens strain LBA4404, and transgenic tobacco plants were generated. Molecular analysis and trypsin activity assay showed that both cDNA and genomic DNA were expressed properly in the transgenic plants. Insecticidal activities in these transgenic plants indicated that transgenic tobacco plants carrying tin2i sequence were more resistant to 2-instar larvae of Heliothis armigera Hubner than those carrying tin2 sequence. Therefore the intron of tin2i sequence might be a contributor to insecticidal activity of the transgenic tobacco.     

农杆菌介导GNA基因对水稻的遗传转化

在ｐＣＡＭＢＩＡ３３００质粒中插入带有ＲＳｓ－１启动子的ＧＮＡ基因,并利用农杆菌介导的遗传转化将其导入水稻的微不定芽受体,得到了再生植株。ＰＣＲ,Ｓｏｕｔｈｅｒｎ ｂｌｏｔ和Ｗｅｓｔｅｒｎ ｂｌｏｔ的检测结果初步证明ＧＮＡ基因已经整合到水稻的基因组中并得到表达。     

利用番茄U3snRNA基因上游启动区构建植物表达载体及对烟草的转化

利用番茄U3snRNA基因上游启动区和ACC合成酶反义RNA-核酶嵌合基因DNA片段,构建含U3snRNA基因上游启动区-ACC合成酶的反义RNA-核酶嵌合序列的表达载体,重组于植物双元表达载体pGA643中,得到pGU3R.用三亲融合法导入农杆菌LBA4404中,采用叶盘法转化烟草,诱导再生小植株,获得了卡那霉素的抗性植株.提取抗性植株总DNA,通过PCR、PCRSouthern杂交检测并分别用启动区序列和ACC合成酶的反义RNA-核酶嵌合序列作探针,通过Southern杂交检测,已筛选出整合有外源基因的转化植株.为进一步研究U3snRNA上游启动区增强反义RNA-核酶基因的表达奠定了基础.     

Construction of a new plant expression vector containing two insect resistant genes and its expression in transgenic tobacco plants

A new plant expression vector (pBS29K-BA) containing two insect resistant genes, a synthetic chimeric gene BtS29K encoding the activated insecticidal protein Cry1Ac and a gene API-BA encoding the arrowhead (Sagittaria sagittifolia L.) proteinase inhibitor (API) A and B, is constructed. Transgenic tobacco plants expressing these two genes are obtained through Agrobacterium-mediated transformation of tobacco leaf discs. The average expression levels of Cry1Ac and API-BA proteins in transgenic plants are of 3.2 μg and 4.9 μg per gram fresh leaf respectively. The results of insecticidal assay of transgenic plants indicate that the pBS29K-BA transformed plants are more resistant to insect damage than the plants expressing the Cry1Ac gene or API-BA gene alone.     

Disease-tolerance of transgenic tobacco plants expressing Ah-AMP gene of Amaranthus hypochondriacus

An antimicrobial peptide gene from Amaranthus hypochondriacus, Ah-AMP, was amplified by PCR and cloned. Sequence analysis results revealed that this gene is 261 bp in length encoding a precursor polypeptide of 87 amino acid residues. Ah-AMP gene was inserted in the binary vector pBin438 to construct a plant expression vector pBinAH916. Leave explants of Nicotiana tabacum var. SR1 were transformed with Agrobacterium tumefaciens LBA4404 harboring the above expression vector. Results from PCR, Southern and Northern blot analyses confirmed that the Ah-AMP gene had been integrated into the tobacco genome and was transcribed at mRNA level. Two bacterial-resistant transgenic plants were selected by inoculating the plants with Pseudomonas solanacearum and statistic analysis of two T1 lines showed that the resistance increased by 2.24 and 1.62 grade and the disease index decreased by 49.6% and 37.3% respectively when compared with the non-transformed control plants SR1. The results from challenging the plants with inoculums of Phytophthora parasitica showed that the symptom development was delayed and disease index was significantly reduced. These results suggest that Ah-AMP gene may be a potentially valuable gene for genetic engineering of plant for disease-resistance.     

苜蓿花叶病毒复制酶基因全长cDNA植物表达载体的构建和对烟草的转化

将苜蓿花叶病毒中国分离株(Alfalfa mosaic virus Chinese isolate，A1MV-Ch)的复制酶P2亚基(90 kD蛋白)基因的全长cDNA构建到植物表达载体pROKⅡ中，得到重组植物表达载体pAIMV-FL．用三亲融合法导入农杆菌LBA4404，并转化烟草，经PCR检测，获得了含全长cDNA的转基因烟草植抹．     

抗人端粒酶逆转录酶单链抗体基因在烟草中的表达

构建了含抗人端粒酶逆转录酶单链抗体基因ScFv-hTERT的植物表达载体p1304-SH,通过农杆菌介导的叶盘法转化烟草.转基因烟草植株叶片总DNA的PCR,Southern b lot检测结果表明,ScFv-hTERT基因已整合进了转基因烟草植株基因组中;RT-PCR,SDS-PAGE分析证实目的基因已在烟草叶片中成功表达,竞争性ELISA的结果表明,表达的重组抗体与其抗原有良好的结合活性.     

Functional analysis of DNA 4 coding region from a Chinese Zhangzhou isolate of banana bunchy top virus

The DNA 4 coding region of banana bunchy top virus from a Chinese Zhangzhou isolate (BBTV-ZZ) is cloned by PCR. The sequencing analysis shows that it is 351 nucleotides long and it putatively encodes a protein of 116 amino acids. On the basis of a plant binary vector pBin438, the plant expression vector pBBTV-4B harboring the BBTV-ZZ DNA 4 coding region has been constructed and then transferred to tobacco (Nicotiana tobacum cv. Xanthi nc) by a Agrobacterium-mediated procedure. Under insect-free condition, movement-defective mutant of CMV-Fny strain (CMV-Fny-△MP) is mechanically inoculated on the lower leaves of transgenic plants. Systemic symptoms with different degrees of severity are developed in the upper uninoculated leaves of transgenic plants at 12 days postinoculation (dpi), while no symptoms can be seen in the uninoculated leaves of untransformed plants at any time. Accumulation of CMV-Fny is detected on the upper uninoculated leaves of transgenic plants, but is not on that of untransformed plants by indirect double antibody sandwich enzyme-link immunosorbent assay (DAS-ELISA). The results reveal that transgenic plants have acquired the property of cell-to-cell movement and systemic spread of CMV-Fny-△MP. This suggests that the protein encoded by BBTV-ZZ DNA 4 might have function of viral movement protein.     

利用人内皮抑素基因构建植物表达载体及对烟草的遗传转化

将人内皮抑素(endostatin)基因重组于植物双元表达载体pGA 643,得到重组质粒pGE.用三亲融合法将其导入农杆菌LBA 4404中,采用叶盘法转化烟草,经诱导与筛选,获得了卡那霉素抗性植株.提取抗性植株总DNA,通过PCR扩增和Sou thern杂交检测,筛选出了整合有外源基因的转化植株.为进一步研究人内皮抑素在烟草中的表达及生物学功能奠定了基础.     

Obtaining High Pest-resistant Tobacco Plants Carrying B.t. insecticidal Gene

To increase the expression level of CryIA(c) gene in transgenic plants, a plant expression vector pBinMoBc carrying the CryIA(c) gene under control of chimeric OM promoter and Ω factor was constructed. As a control, pBinoBc carrying the CryIA(c) gene with the CaMV 35S promoter was also constructed. The vectors were transferred into tobacco plants respectively via Agrobacterium-mediated transformation. ELISA assay showed that the expression level of the CryIA(c) gene in pBinMoBc transgenic tobacco plants was 2.44-times that in pBinoBc transgenic tobacco plants, and it could be up to 0.255% of total soluble proteins. Bioassay showed that pBinMoBc transgenic tobacco plants had more notable insecticidal effect than pBinoBc transgenic tobacco plants. The above results showed that the chimeric OM promoter was a stronger promoter than CaMV 35S promoter that was widely used in plant genetic engineering, and this is very useful in pest-resistant plant genetic engineering.     

农杆菌介导的双价抗虫基因对番茄遗传转化的研究

采用农杆菌介导法将含有苏云金芽孢杆菌毒蛋白基因(CryIAc)与半夏凝集素抗虫基因(Pta)的高效植物表达载体pCAMBIA3300转入番茄品系Micro Tom的子叶外植体中。经过共培养、除草剂筛选和分化再生,获得了24个具有除草剂抗性的株系。再将转化后的番茄植株经过PCR检测和Southern Blot检测,确定检测后呈阳性反应的株系为8个。通过小菜蛾幼虫初步抗性试验证明,转基因株系表现出较强的抗虫性。实验结果为进一步研究番茄抗虫性和培育抗虫番茄新品种奠定了重要基础。     

Obtaining the transgenic poplars with low lignin content through down-regulation of 4CL

The antisense 4CL (4-coumarate: CoA ligase)gene was transformed into triploid Chinese white poplar(Populus tomentosa) mediated by Agrobacterium tumefaciens.PCR and Southern blot analysis indicated that antisense 4CLgene had been integrated into the genome of the transgenicChinese white poplars. The antisense gene had also beenexpressed, which was indicated by RT-PCR and Westernanalysis. Klason lignin content assay showed that repressionof 4CL expression could result in remarkable reduction oflignin content in transgenic poplars, with most reduction of 41.73% compared with that of wild type in this paper. Butthere is no significant difference in holocellulose content be-tween trans- genic and wild poplars. We considered that 4CLmight not be the metabolism control point between ligninand carbohy- drate biosynthesis. The stems of transgenicpoplars displayed red-brown color with different levels afterthe bark was peeled, while those of untransformed plantswere white. No visible differences in growth and developmentwere observed between transgenic and wild plants. Wiesnerreaction analysis of the transgenic plant stems with reducedlignin content exhibited red color, while that of untrans-formed plant was typically purple-red.     

农杆菌介导法的植物遗传转化

农杆菌介导的基因转化是一种使外源DNA转移到目的植株的天然系统,通过植物表达载体上DNA的加工与转移将外源DNA转运到植物细胞中。因其具有易操作、低费用、高效率、插入片段确定性好和转基因拷贝数低等独特优点,已经成为转基因策略中的首选方法,在植物的遗传转化中得到广泛应用。     

转几丁质酶基因烟草对三种真菌拮抗作用的研究

几丁质酶广泛存在于高等植物体内,它可以分解真菌细胞壁中的几丁质,破坏其细胞结构,从而获得对真菌的抗性.试验以转苦瓜几丁质酶基因烟草(T-Chit)为供试植物,测定植株根系和叶片内几丁质酶活性,选取了3种具有代表性的真菌:毛霉、木霉、禾谷镰刀霉,通过抑菌试验验证了T-Chit组织萃取液对真菌的抗性.结果表明:1)T-Chit几丁质酶活性显著高于非转基因烟草(Nt-X),且转基因烟草根系几丁质酶活性比叶片高86%;2)T-Chit组织萃取液对毛霉生长具有明显抑制作用,根系强于叶片;3)T-Chit对木霉和禾谷镰刀霉的抑制具有时空效应:抑菌效果与植株部位及作用时间有关.     

转乙肝病毒表面抗原基因烟草发根的获得

构建了乙肝病毒表面抗原基因（HBsAg）植物表达载体,通过冻融法将HBsAg 基因转入到发根农杆菌LBA1314中,采用叶盘法将HBsAg基因导入到烟草中,获得了转基因烟草发根.对转基因烟草发根的GUS检测结果表明：转HBsAg基因烟草发根可以染成蓝色,而非转基因烟草的根没有染色反应.这说明gus基因在转HBsAg基因烟草发根获得了表达.     

胰蛋白酶抑制剂抗虫基因转化烟草的研究

实验用携带质粒pAM194/TI的根癌农杆菌LBA4404转化烟草,通过筛选,共获得35株卡那霉素抗性苗.GUS组织染色、PCR检测及抗虫试验表明胰蛋白酶抑制剂抗虫基因已经成功地整合进再生植株染色体基因组中,有些已正确表达.     

表达雪花莲外源凝集素基因的油菜转基因植株的获得

利用农杆菌素LBA4404（pCAMBIA3300RG)转化优良甘蓝型油菜恢复系W723的下胚轴节段.pCAM-BIA3300RG含有Rssl启动子引导的雪花莲外源凝集素基因（gna）和CaMV-35S启动子引导的除草剂抗性基因（bar）。经过两轮除草剂（2.5mg/L bialaphos）筛选（两周/轮）,除草剂抗性再生芽被传入生根培养基中生根,对根系旺盛生长的植株中所含gna基因进行PCR分析,PCR分析证实了这些植株确为转基因植株,利用Western印迹法对随机选择的5株含gna基因的转基因植株的分析发现,其中4株表达了gna基因。目前正对这些表达gna基因的转基因植株进行后代遗传分离分析。     

Transgenic tobacco plants expressing synthetic Cry1Ac and Cry1Ie genes are more toxic to cotton bollworm than those containing one gene

Transgenic tobacco plants carrying Cry1Ac, Cry1Ie or both genes were obtained. In the leaves of transgenic plants carrying both genes, the contents of Cry1Ac and Cry1Ie proteins were 0.173% and 0.131% of the total proteins, respectively. Cry1Ac protein content was 0.182% and Cry1Ie protein con- tent was 0.124% of the total proteins in the leaves of transgenic plants containing only one Bt gene. Fresh leaves of transgenic tobacco and wild-type plants were used for the insect bioassay against wild-type and Cry1Ac-resistant cotton bollworm (Helicoverpa armigera). The bioassay results showed that transgenic plants carrying both genes were significantly more toxic to wild-type and Cry1Ac-resistant cotton bollworm than those carrying Cry1Ac or Cry1Ie alone. This study indicates that the higher toxicity of transgenic tobacco plants carrying both genes is caused by the cooperative function of both Bt proteins, thus providing a potential way to delay the development of insect resis- tance to transgenic crops.     

Inheritance and expression of multiple disease and insect resistance genes in transgenic rice

2—3 anti-fungal disease genes are coinserted with hygromycin phosphotransferase in the same vector. Two insecticidal genes and PPT acetyl transferase genes are placed in another one. The vectors are co-delivered to rice embryonic cellus tissue at a molar ratio of 1︰1 using the particle gun method. 55 independent regenerated lines have been obtained through screening for hygromycin resistance. Of these, 70% transgenic plants harbor 6—7 foreign genes. The genes on the same vectors are always co-delivered to rice plant. Northern blot analysis has indicated that the multiple foreign genes give stable expression. In the 6 transgenic plants carrying 6—7 foreign genes, multiple foreign genes tend to integrate in 1 or 2 genetic loci. Progeny segregation is consistent with Mendel’s 3︰1 segregation law. 8 homozygous R₁ transgenic plants harboring 2—3 anti-fungal and 2 insecticidal genes are selected from large number of transgenic progeny screening for hygromycin and Basta resistance.