抗草甘膦抗虫植物表达载体的构建及其转基因烟草的分析

构建了含草甘膦抗性突变基因（aroAM12）和人工合成重组Bt抗虫基因（Bts1m）的植物表达载体pCM12_s1m。aroAM12基因的表达由CaMV35S启动子控制,Bts1m基因的表达由2E_CaMV35S启动子和Ω因子控制。通过农杆菌介导,将aroAM12和Bts1m基因转化到烟草中,转基因烟草通过在含草甘膦的MS培养基上筛选而获得。Southern blot分析表明所有经过草甘膦筛选出的转化植株都整合有aroAM12基因,约70%的转化植株同时整合有aroAM12和Bts1m基因。Northern blot、Immunodot blot分析进一步证明整合的两个基因在转录、翻译水平上均进行了表达,不同植株之间表达存在着差异。草甘膦抗性和虫试实验证明,获得的转基因烟草对草甘膦和烟青虫具有很强的抗性。     

Epsps基因为筛选标记的多基因抗虫表达载体构建

目的:为了获得水稻的广谱抗虫性,同时也避免由潮霉素抗性基因引起的安全性问题.构建以抗除草剂基因(Epsps 基因)为筛选标记的多基因抗虫植物表达载体 pCTSK.方法:以双元载体pCAMBIA1300为基础,将潮霉素抗性基因hpt替换成携带烟草叶绿体转运肽序列TSP的草甘膦抗性突变基因aroAM12(编码细菌5-烯醇式丙酮酸莽草酸-3-磷酸合成酶Epsps)作为筛选标记基因,获得中间表达载体pCISM1300.然后再连接上3个抗虫基因(马铃薯蛋白酶抑制剂基因Pin-Ⅱ、苏云金杆菌毒蛋白基因Bt cryI(A)及雪花莲外源凝集素基因 CNA)的完整表达片段(包含各自的启动子和终止子).结果:通过PCR方法和酶切方法鉴定已成功地构建了该表达载体;通过不同实验方案的数据分析,得出在载体构建的大分子连接中优化的一次连接法连接效率高于二次连接法的结论.     

使用双抗真菌蛋白基因提高水稻抗病性的研究

将含有串联的RC24基因和β-1,3－Glu基因的pGB12质粒与含有hpt基因的p35H质粒用基因枪法同时导入华南地区一优良籼稻（OryzasativaL．ssp．indica）品种“七丝软占”中。Southernblot分析证明获得17个同时整合有RC24基因和β-1,3－Glu基因的转基因系。而Northernblot分析表明在不同的转基因系中两基因的表达量存在很大差异。对R1及R2代转基因植株的分子分析表明,这两个基因已稳定遗传到R1、R2代,并在RNA水平上持续表达。转基因植株苗期抗稻瘟病试验表明,部分R1代转基因植株苗对广东省稻瘟病菌（Magnaphorthagrisea）中的5个代表菌株表现出不同程度的抗性提高。而其中18株抗性提高的R1代转基因植株的R2代各苗对广东省稻瘟病菌优势生理小种中的3个代表菌株表现出一致的抗性提高,结合分子分析,初步证明获得10株整合有RC24和β-1,3－Glu双基因的稻瘟病抗性提高的R1代转基因纯系植株。且这些转基因纯系植株的离体叶片对纹枯病菌（RhizoctoniaSolaniKuhn的抗性也明显提高。     

利用花青素可视化跟踪表达系统快速筛选表达Cry1Ab/c基因的转基因玉米

以草甘膦抗性基因Epsps为标记基因, 在原核Kan^r基因两侧引入Cre(环化重组酶)基因识别的Lox-P位点, 同时以编码花青素合成转录因子的Bi和Cl基因为可视化选择报告基因, 构建了Bt杀虫蛋白基因Cry1Ab/c的可视化跟踪表达载体pBAC9017。用PDS1000/He基因枪转化玉米(Zea mays)自交系501的幼胚和胚性愈伤组织, 获得147个草甘膦抗性的玉米再生植株。其中106棵植株获得了结实种子, 16棵植株的结实种子有紫红色花青素基因的表达。经PCR检测表明, 外源Cry1Ab/c基因已经整合到玉米的基因组中。转基因植株种子蛋白粗提物用BT-Cry1Ab/1Ac金标免疫检测试纸条和ELISA检测, 结果表明, Cry1Ab/c在部分转基因植株后代中表达。     

转OsMAPK4基因烟草的抗旱性研究与遗传分析

以低温处理的水稻辽盐241植株叶片总RNA为模板, 用OsMAPK4基因特异引物通过RT-PCR扩增出OsMAPK4基因, 构建了由E12启动子调控的OsMAPK4基因植物表达载体pBME12。通过农杆菌介导法将OsMAPK4基因导入烟草, 筛选获得25株转基因植株。抗旱性研究结果表明, OsMAPK4基因的超量表达提高了T1代转基因植株的抗旱性。卡那霉素抗性在T1代转基因植株中的分离情况表明, 大多数转基因株系符合单基因遗传规律。     

CP4-EPSPS转基因棉花植株鉴定方法比较分析

CP4-EPSPS是从土壤农杆菌CP4菌株中分离得到的抗除草剂草甘膦基因,是转基因植物研究中最为常用的一种筛选标记基因。但是在CP4-EPSPS转基因植物后期筛选过程中仅凭简单的草甘膦抗性筛选并不能得到完全准确的鉴定结果,常会出现假阳性或漏选的情况。本研究以抗草甘膦转CP4-EPSPS基因棉花为材料,对PCR扩增、ELISA、CP4-EPSPS蛋白检测试纸条及草甘膦抗性四种转基因阳性植株筛选方法进行比较,从筛选结果的准确性、时效性、易用性及实惠性等不同方面综合分析了各种筛选方法的优缺点,结果表明ELISA、试纸条检测方法的准确性显著高于PCR检测与0.3%浓度草甘膦抗性检测,而试纸条检测操作更加便捷,因此建议将草甘膦抗性与试纸条检测方法结合起来使用。本研究结果为以CP4-EPSPS基因为标记筛选的转基因植物的室内及大田筛选提供实验依据。     

利用微滴数字PCR方法快速分析转基因玉米中外源基因的拷贝数

以玉米自交系501幼胚为受体材料,首先将来自球形节杆菌的EPSPS基因(G23V)按玉米密码子偏爱性进行优化与人工合成,并且将其克隆到表达载体pBAC9200中;然后利用农杆菌介导法将质粒载体转入玉米自交系501的幼胚中。经过愈伤诱导、草甘膦抗性筛选和分化培养最终获得14株转化再生植株。经PCR、RT-PCR检测表明,其中5株目的基因G23V-EPSPS稳定整合且在转录水平获得表达。随后,利用微滴数字PCR技术对外源基因拷贝数进行了检测分析,分析结果表明在5株阳性转基因植株中,外源基因G23V-EPSPS拷贝数分别为0.12、1.0、0.9、1.89和0.66,介于0~2之间。成功建立了草甘膦抗性基因G23V-EPSPS在玉米中的遗传转化体系,为以新型高抗草甘膦G23V-EPSPS基因作为转基因玉米筛选标记基因奠定了基础;而且以微滴数字PCR技术代替传统的Southern Blot简便快速的完成外源基因拷贝数的分析,为微滴数字PCR技术在转基因外源基因拷贝数检测上的广泛应用做了初步的探索。     

转石蒜凝集素基因烟草的抗蚜虫性

利用农杆菌介导法将质粒pBILRA转化烟草(Nicotianatabacum L.),该质粒含有由花椰菜花叶病毒35S启动子(CaMV35S)引导的筛选基因新霉素磷酸转移酶基因(nptⅡ)及石蒜凝集素基因(lra).通过卡那霉素筛选获得了25株独立转基因烟草植株.Western blot分析表明,石蒜凝集素蛋白在不同转基因植株中表达量不同.对转基因T1代植株的遗传分析表明,lra基因在大多数独立转基因植株后代中以孟德尔3:1的分离比方式遗传.抗虫试验表明,表达较高水平石蒜凝集素蛋白的转基因烟草对桃蚜种群的生长具有明显的抑制作用.首次报道了表达石蒜凝集素基因的烟草对蚜虫具有抗性.石蒜凝集素基因可用于植物抗虫基因工程研究及应用.     

外源基因在烟草绿色组织中的高效表达研究

研究外源基因在受体绿色组织中的特异表达情况,分别构建由棉花PsbP启动子驱动的GUS基因及CP4 epsps 基因的植物表达载体pBI121-P、pBI121-PE.农杆菌介导法转化到烟草中,获得20株转pBI121栽体、40株转pBI121-P栽体和32株转pBI121-PE载体的烟草阳性植株.组织化学染色分析表明,GhPsbP启动子驱动的GUS基因只在转基因烟草的叶片和茎中表达,在根中不表达;Real-time PCR分析表明,PsbP启动子驱动CP4 epsps基因在叶和茎中的表达量分别是根中的15倍和10倍;草甘膦抗性试验证明,PsbP启动子驱动的CP4 epsps基因在烟草叶及茎的绿色组织中的表达量足以忍受1%浓度草甘膦的毒害.证明GhPsbp启动子可以有效地驱动外源基因在烟草的绿色组织中高效特异的表达.     

棉花乙烯合成基因促进拟南芥和烟草不定根发生的研究

从棉花纤维cDNA中克隆获得乙烯合成基因GhACO3,构建了植物过量表达载体p35S::GhACO3.通过花序侵染法和叶盘法分别转化拟南芥和烟草,利用卡那霉素筛选及分子检测获得转基因阳性拟南芥和烟草植株.结果表明,GhACO3基因已整合到拟南芥和烟草基因组中;经过纯合筛选后获得转基因T2代拟南芥植株;与野生型拟南芥相比,GhACO3基因对拟南芥不定根发生具有显著促进作用;与野生型烟草植株相比,转GhACO3基因烟草不定根发生得到了显著的促进.研究表明,GhACO3基因的过量表达能够促进拟南芥和烟草不定根的形成发育,为进一步探讨GhACO3的生物学功能和进行转基因育种奠定了基础.     

干旱耐逆基因（HS1）转化甘薯获得转基因植株

以甘薯（1pomoeabatatas（L.）Lam．）品种栗子香的胚性悬浮细胞为受体材料,用根癌农杆菌介导法,获得了表达除草剂抗性基因bar基因的转HSl基因甘薯植株。共计380个遗传转化的胚性细胞团,在添加2mg／L2．4-D、100mg／L Carb和10mg／L Glu（glufosinate）的固体Ms培养基上选择培养9周后,得到了12个Glu抗性愈伤组织。将这些抗性愈伤组织转移到添加1mg／L ABA、100mg／L羧苄青霉素和10mg／L Glu的固体MS培养基上,其中的3个抗性愈伤组织再生出拟转基因植株。PCR鉴定它们为转基因植株。Southern blot分析表明,HS1基因已整合到基因组中。转基因植株具有稳定的除草剂抗性。结薯观察实验结果表明,转基因植株结薯正常。     

通过转重复结构的ACC氧化酶基因延长香石竹的瓶插期

以香石竹叶片为外植体,用农杆菌(Agrobacteriumtumefaciens)介导法,在选择分化培养基中培养后,将香石竹重复结构的ACC氧化酶(ACO)基因核DNA导入香石竹‘Maber品种.经Southera杂交检测,证明外源基因已整合到香石竹基因组,共获得3株转化植株.转基因植株在隔离条件下栽培时正常开花,转基因T257株系切花衰老过程中乙烯释放量较对照低95%,没有乙烯跃变峰出现.在25℃条件下比较瓶插期,有2个转化株系瓶插期显著延长,最长比对照长了5 d以上.     

Cell suspension culture-mediated incorporation of the rice bel gene into transgenic cotton

Cotton plants engineered for resistance to the herbicides, glyphosate or glufosinate have made a considerable impact on the production of the crop worldwide. In this work, embryogenic cell cultures derived from Gossypium hirsutum L. cv Coker 312 hypocotyl callus were transformed via Agrobacterium tumefaciens with the rice cytochrome P450 gene, CYP81A6 (bel). In rice, bel has been shown to confer resistance to both bentazon and sulfanylurea herbicides. Transformed cells were selected on a liquid medium supplemented alternately or simultaneously with kanamycin (50mg/L) and bentazon (4.2 μmol). A total of 17 transgenic cotton lines were recovered, based on the initial resistance to bentazon and on PCR detection of the bel transgene. Bel integration into the cotton genome was confirmed by Southern blot and expression of the transgene was verified by RT-PCR. In greenhouse and experimental plot trials, herbicide (bentazon) tolerance of up to 1250 mg/L was demonstrated in the transgenic plants. Transgenic lines with a single copy of the bel gene showed normal Mendelian inheritance of the characteristic. Importantly, resistance to bentazon was shown to be stably incorporated in the T1, T2 and T3 generations of self-fertilised descendents and in plants outcrossed to another upland cotton cultivar. Engineering resistance to bentazon in cotton through the heterologous expression of bel opens the possibility of incorporating this trait into elite cultivars, a strategy that would give growers a more flexible alternative to weed management in cotton crops.     

Recovery of transgenic plants by pollen-mediated transformation in <Emphasis Type="Italic">Brassica juncea</Emphasis>

The aroA-M1 encoding the mutant of 5-enolpyruvyl-shikimate-3-phosphate synthase (EPSPS) was introduced into the Brassica juncea genome by sonication-assisted, pollen-mediated transformation. The plasmid DNA and collected pollen grains were mixed in 0.3 mol/L sucrose solution and treated with mild ultrasonication. The treated pollen was then pollinated onto the oilseed stigmas after the stamens were removed artificially. Putative transgenic plants were obtained by screening germinating seeds on a medium containing glyphosate. Southern blot analysis of glyphosate-resistant plants indicated that the aroA-M1 gene had been integrated into the oilseed genome. Western blot analysis further confirmed that the EPSPS coded by aroA-M1 gene was expressed in transgenic plants. The transgenic plants exhibited increased resistance to glyphosate compared to untransformed plants. Some of those transgenic plants had considerably high resistance to glyphosate. The genetic analysis of T₁ progeny further confirmed that the inheritance of the introduced genes followed the Mendelian rules. The results indicated that foreign genes can be transferred by pollen-mediated transformation combined with mild ultrasonication.     

Lack of glyphosate resistance gene transfer from Roundup Ready soybean to Bradyrhizobium japonicum under field and laboratory conditions

A field study was conducted at the Russell E. Larson Agricultural Research Center to determine the effect of transgenic glyphosate-resistant soybean in combination with herbicide (Roundup) application on its endosymbiont Bradyrhizobium japonicum. DNA of bacteroids from isolated nodules was analysed for the presence of the transgenic 5-enolpyruvylshikimate-3-phosphate synthase (CP4-EPSPS) DNA sequence using polymerase chain reaction (PCR). To further assess the likelihood that the EPSPS gene may be transferred from the Roundup Ready (RR) soybean to B. japonicum, we have examined the natural transformation efficiency of B. japonicum strain 110spc4. Analyses of nodules showed the presence of the transgenic EPSPS DNA sequence. In bacteroids that were isolated from nodules of transgenic soybean plants and then cultivated in the presence of glyphosate this sequence could not be detected. This indicates that no stable horizontal gene transfer (HGT) of the EPSPS gene had occurred under field conditions. Under laboratory conditions, no natural transformation was detected in B. japonicum strain 110spc4 in the presence of various amounts of recombinant plasmid DNA. Our results indicate that no natural competence state exists in B. japonicum 110spc4. Results from field and laboratory studies indicate the lack of functional transfer of the CP4-EPSPS gene from glyphosate-tolerant soybean treated with glyphosate to root-associated B. japonicum.     

ACC合成酶基因及其反义基因对西瓜的遗传转化

以2日龄西瓜(Citrullus lanatus(Thunb.)Mansfeld)无菌苗子叶为外植体,通过与根癌农杆菌(Agrobacterium tumefaciens)进行叶盘共培养建立了西瓜的遗传转化系统。所用根癌农杆菌中含有改建后分别携带嵌合NPTⅡ基因和番茄的ACC合成酶基因及其反义基因的质粒。外植体在MSA培养基(MS盐类、B_5维生素、1.0mg/L BA、0.2mg/L IAA)上预培养3～4d后,与根癌农杆菌共培养4d,随后转移外植体至附加100mg/L卡那霉素、300mg/L头孢菌素的MSA培养基上筛选转化芽。将带芽外植体移入含有100mg/L卡那霉素、300mg/L头孢菌素的伸长培养基(MS 0.2mg/L KT)上进行芽伸长,切取2～3cm高的伸长芽移入生根培养基(1/2MS 0.1mg/L NAA)生根。Southern blot结果证明获得转基因植株,乙烯释放指标表明转入的正义和反义ACC合成酶基因得到不同程度的表达。     

带npt-Ⅱ基因转基因水稻快速检测技术的建立

以转溶菌酶基因水稻纯系材料中花9号(ZH9(R))及其受体品种中花9号(ZH9(CK))为材料, 以ZH9(R)中携带的npt-Ⅱ基因作为辅助筛选标记, 利用抗生素对其进行处理, 建立了一套快速检测带npt-Ⅱ基因转基因水稻的技术体系。使用不同浓度的卡那霉素(Kanamycin, Kan)和G418溶液将ZH9(R)和ZH9(CK)成株离体叶片于室内室温下置于培养皿中浸泡处理, 通过观察叶片变化, 确定G418为检测带npt-Ⅱ基因转基因水稻的最佳抗生素, 将G418(溶液)80 mg/L浓度(处理4天)作为检测该类转基因水稻成株离体叶片的临界浓度。进一步用G418对ZH9(R)和ZH9(CK)种子、幼胚和幼苗进行了不同处理。确定: (1) G418(溶液)300 mg/L浓度(处理7天)作为检测该类转基因水稻种子的临界浓度; (2) G418(1/2 MS+0.5 mg/L 6-BA+1.5%蔗糖培养基)200 mg/L浓度(处理10天)作为检测该类转基因水稻幼胚的临界浓度; (3) G418(1/2 MS+0.5 mg/L 6-BA+1.5%蔗糖培养基)150 mg/L浓度(处理12天)作为检测该类转基因水稻幼苗的临界浓度, 并且通过PCR方法证实了上述结论。将这些结论应用于ZH9(R)转育后代叶片、种子、幼胚和幼苗群体的检测, 检测效果都非常明显。这为带npt-Ⅱ基因转基因水稻建立了一套简便、直观且准确的检测方法。     

Agrobacterium-mediated transformation of cotton (Gossypium hirsutum L. cv. Zhongmian 35) using glyphosate as a selectable marker

The most economically significant Chinese cotton cultivar (Gossypium hirsutum L. cv. Zhongmian 35) was transformed via Agrobacterium tumefaciens-mediated DNA transfer. The aroA-M1 gene that confers resistance to the glyphosate was fused with a chloroplast-transit peptide of Arabidopsis thaliana 5-enolpyruvyl-3-phosphoshikimate synthase (ASP) and expressed in cotton plants under the control of a CaMV35S promoter. Transgenic plants were directly selected on medium containing glyphosate. Thirty-four independent transgenic lines were obtained after selection, giving a maximal 1.9% transformation frequency. The integration and expression of the aroA-M1 gene in T₀ plants and T₁ progeny were confirmed using DNA hybridization, Western blot and PCR techniques. An increased resistance of T₀ and T₁ transgenic plants towards glyphosate was also observed.     

Simultaneous substitution of Gly96 to Ala and Ala183 to Thr in 5-enolpyruvylshikimate-3-phosphate synthase gene of <Emphasis Type="Italic">E. coli</Emphasis> (k12) and transformation of rapeseed (<Emphasis Type="Italic">Brassica napus</Emphasis> L.) in order to make tolerance to glyphosate

Glyphosate is a non-selective broad-spectrum herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). This is a key enzyme in the aromatic amino acid biosynthesis pathway of microorganisms and plants. The manipulation of bacterial EPSPS gene in order to reduce its affinity for glyphosate, followed by its transfer to plants is one of the most effective approaches for the production of glyphosate-tolerant plants. In this study, we chose to focus on amino acid residues glycine96 and alanine183 of the E. coli (k12) EPSPS enzyme. These two amino acids are important residues for glyphosate binding. We used site directed mutagenesis (SDM) to induce point mutations in the E. coli EPSPS gene, in order to convert glycine96 to alanine (Gly96Ala) and alanine183 to threonine (Ala183Thr). After confirming the mutation by sequencing, the altered EPSPS gene was transferred to rapeseed (Brassica napus L.) via Agrobacterium-mediated transformation. The transformed explants were screened in shoot induction medium containing 25 mg L⁻¹ kanamycin. Glyphosate tolerance was assayed in putative transgenic plants. Statistical analysis of data showed that there was a significant difference between the transgenic and control plants. It was observed that transgenic plants were resistant to glyphosate at a concentration of 10 mM whereas the non-transformed control plants were unable to survive 1 mM glyphosate. The presence and copy numbers of the transgene were confirmed with PCR and Southern blotting analysis, respectively.