蓖麻毒蛋白A链基因RNAi转化研究

通过基因沉默技术调控蓖麻毒蛋白A链基因的表达,以期获得低毒蓖麻新材料.利用基因克隆技术获得蓖麻毒蛋白A链基因762 bp片段,命名为RTA基因.进一步利用该基因构建了植物RNAi表达载体pBI-RTA-S-AS,通过农杆菌介导法转化蓖麻子叶节,用卡那抗性筛选转化再生植株,PCR进一步鉴定转基因植株.结果表明:克隆得到目的基因长762 bp,与预期结果一致;卡那抗性筛选和PCR鉴定结果显示,获得了3株转基因阳性植株.     

蛋白激发子基因peaT1转基因棉花的获得及初步鉴定

将来源于极细链格孢菌的蛋白激发子基因pesT1克隆到植物表达载体pCAMBIA2300上,成功构建了含有增强子和多联终止子的植物表达载体pCAM BI A2300-G4AS-peaT1.通过花粉管通道法转化棉花,经卡那霉素抗性筛选、PCR和RT-PCR检测获得一株转基因棉花植株,其植株茎粗和成铃数均高于非转基因对照株.     

野生罂粟RNAi表达载体的构建及遗传转化

通过PCR方法从质粒pGEM-bc中克隆野生罂粟BBE-COR融合基因片段约760 bp,以pHANNIBAL和植物表达载体pCAMBIA3300为基础,将克隆到的BBE-COR融合基因正向和反向片段分别插入pdk内含子的两边,经酶切、PCR鉴定及序列分析表明,特异性RNAi表达载体p3300-pHR构建成功.采用直接转化法,将重组子导入根癌农杆茵AGL1中.以野生罂粟茎尖生长点为转化受体,用农杆茵介导法将目的基因转入野生罂粟中.经卡那霉素和除草剂筛选后,共获得53株转基因植株,PCR检测后,其中14株表现阳性,可初步确定目的基因已经整合到野生罂粟基因组中.     

转小麦冷胁迫蛋白截短基因烟草及其抗病性分析

TA3-13是克隆于小麦冷胁迫蛋白基因的截短片段。原核表达的TA3-13蛋白能够诱导烟草产生显著的抗烟草花叶病毒(TMV)的作用。文章将TA3-13基因片段克隆到植物表达载体pBI121上,构建成转基因重组体pB-3-13,通过冻融法转化农杆菌EHA105,构建成转基因侵染菌株。采用叶盘法将pB-3-13转化三生烟草,经卡那霉素抗性筛选,获得48株T0代再生植株。通过PCR检测,鉴定出33株转基因单株,收获了20株种子作为T1代株系。PCR-Southern杂交结果显示,PCR阳性条带与TA3-13探针有特异性杂交,说明外源基因被转化到烟草的基因组中。选取两个T1代株系的烟草植株用于各项测定。GUS组织化学活性鉴定和RT-PCR检测结果显示,外源基因可以成功地表达。接种TMV病毒后,转基因烟草抗TMV的能力较转空载体烟草提高3～5倍。转基因烟草具有抗TMV侵入和抗病毒病害发展的作用,同时转基因烟草可以抗细菌软腐病菌的扩展。     

导入Ghabp1基因对烟草叶细胞发育的影响

将棉花生长素结合蛋白基因cDNA与CaMV35S启动子和NOS终止子融合,构建了一个新的表达载体pGABP1-121,采用农杆菌介导法转化烟草,经过分化、筛选和再生,得到了具有卡那霉素抗性的植株。抗性植株经PCR及Southern杂交检测,证明外源目的基因已经整合到烟草基因组中。扫描电镜观察发现转基因烟草与对照相比叶细胞增大,结果表明,棉花生长素结合蛋白基因的表达影响了烟草叶细胞的发育。     

茎尖法转基因棉花植株真实性鉴定方法探究

棉花茎尖转化法具备不受基因型限制、转化周期短的优点,是理想的棉花转化体系,但据报道其所获得的转基因植株普遍存在遗传不稳定、高代植株基因丢失的现象。以陆地棉TM?1品种为受体材料,利用茎尖转化法将DsRed2载体转入棉花,经卡那霉素筛选获得16株抗性植株,进一步PCR扩增靶基因,获得6株DsRed2基因片段PCR检测为阳性的植株,初步判断该6株为茎尖转化法获得的转基因植株,但经紫外照射,6个转基因植株均未检测到红色荧光。对其进行靶基因RT?PCR,发现DsRed2基因在6个转基因植株中仅有极低量的表达或无表达。进一步对DsRed2载体的非T?DNA片段,即载体骨架部分进行PCR以及植株内生菌培养检测,结果表明,6个转基因植株均含有完整的DsRed2载体,植株可培养出含有完整载体的内生菌,且内生菌经农杆菌16S核糖体RNA（16S rRNA）片段PCR检测结果为阳性,推测由于茎尖侵染形成农杆菌与植株共生关系,造成假阳性株的现象,进而导致高代转基因植株基因丢失、遗传不稳定的现象。旨在建立一套完整的茎尖法转基因棉花植株真实性的鉴定方法,为进一步深入研究提供参考依据。     

隐地蛋白(cryptogein)基因定点突变及其广谱抗病烟草转化植株的获得

用PCR法从隐地疫霉 (Phytophthoracryptogea)基因组DNA中克隆了cryptogein(Cry)基因。将Cry基因的 13位赖氨酸 (K)突变成缬氨酸 (V) ,获突变基因CryK13V ,并将其构建于CaMV35S启动子控制的植物表达载体上。通过农杆菌介导的叶盘转化法转入烟草 ,经卡那霉素抗性筛选获 33株再生植株 ,PCR检测和Southern杂交分析表明CryK13V基因已整合到烟草基因组中。接种试验结果表明 ,转基因烟草植株对黑胫病菌、赤星病菌和野火病菌等的抗性均有提高。Northern杂交分析表明 ,微弱的CryK13V基因在转化植株中的表达就足以激活PR1和OPBP1等防卫反应相关基因的表达 ,而且表达丰度与转基因植株的抗病性有着一定的正相关性。研究结果还表明 ,隐地蛋白13位上的赖氨酸在诱导细胞死亡中起着关键的作用。     

表达尾穗苋凝集素基因的转基因烟草对桃蚜(Myzus persicae)繁殖的影响

为研究尾穗苋凝集素(ACA)在植物中可能的抗虫作用,通过RH-PCR克隆了ACA cDNA并通过RACE分析证实了cDNA序列的正确性.构建了ACA基因的韧皮部特异表达载体pBCACAc并通过根癌杜菌介导转化了烟草(Nicotiana tabacum L.).PCR和Southern blot分析结果证明,ACA基因已经整合到转化再生植物的基因组中,其插入插贝数1~4个不等.对转基因烟草叶片蛋白时行行免疫反应的结果表明,ACA基因已被转录和翻译.用桃蚜(Myzuspersicae Sulzer)对转基因烟草离体叶片进行了的接虫试验结果表明,测试过的78%的烟草对桃蚜口密度增长的平均抑制率在75%以上,在抗性植株上观察到有桃蚜若虫死亡的现象.以上结果表明,ACA基因是一个有效的抗蚜基因,在作物抗蚜分子育种具有应具应用价值.     

激发子基因peaT1转化三生烟及其对TMV抗性的提高

通过根癌农杆菌(Agrobactrium tumefaciens)介导转化法,将含有激发子基因peaT1的植物表达载体pCAM-BIA2300-G4AS-peaT1转化三生烟,获得了转基因烟草植株。用PCR检测确认了阳性转化株,用Southern杂交、RT-PCR和Western杂交进一步证实了peaT1基因的整合、转录和表达。对T1代转基因阳性株进行TMV接种试验,结果显示,与非转基因对照相比,表达peaT1的烟草叶片枯斑数量减少,表明蛋白激发子基因peaT1的表达提高了转基因烟草对TMV的抗性。     

桃ACO基因反义转化桃幼胚子叶的研究

用根癌农杆菌(Agrobacterium tumefaciens )和基因枪两种方法,以桃(Prunus persica L. Batsch)幼胚子叶为受体,转化桃ACC氧化酶（ACO）反义基因片段,经筛选培养获得了卡那霉素抗性芽。微芽嫁接培养抗性芽部分可成株。PCR、Southern 杂交和GUS基因表达等分子检测,初步表明外源反义ACO基因已经整合到桃基因组中。     

表达尾穗苋凝集素基因的转基因烟草对桃蚜(Myzus persicae)繁殖的影响(英文)

To investigate the possible function of the agglutinin from Amaranthus caudatus L. (ACA) in plant defending against insect pests, ACA cDNA was cloned by RT-PCR and the 5‘ and 3‘ sequences were confirmed by rapid amplification of cDNA ends (RACE). The phloem-specific expression vector of ACA gene, pBCACAc, was constructed based on the plant binary vector pBC438 and transfered into tobacco plants via Agrobacterium-mediated transformation method. Results from PCR and Southern blotting analysis showed that AOA gene was integrated into the genomes of transformed plants and the transgene integration varied from one to four estimated copies per genome. Western blotting analysis indicated that ACA gene was transcribed and translated in the transgenic plants. The bioassay of Myzus persicae Sulzer on detached leaves demonstrated that the 78% transgenic tobacco plants displayed an average aphid-resistant rate of more than 75%. Some apterous progeny of M. persicae were found dead on the resistant plants. These results indicate that ACA gene should be an effective aphid-resistant gene and could be valuable for application in crop breeding for aphid resistance.     

蓄势待发的印度生物技术产业

构建的重组表达质粒pPIC9K-HSA-IFNα-2b经限制性内切酶SalI酶切线性化后电转化巴斯德毕赤酵母菌（P.Pastoris）SMD1168,将阳性转化子用甲醇诱导表达并进行PCR鉴定和Mut表型鉴定,再用Western-Blot法及Wish细胞-VSV病毒系统来鉴定表达蛋白的免疫原性及生物活性,同时,在摇瓶培养条件下,初步研究了甲醇诱导浓度及菌体诱导的起始OD值两因素对目的蛋白表达量的影响,本研究成功表达出具有高生物学活性的白蛋白融合干扰素蛋白（HSA-IFNα-2b）,对摇瓶发酵表达条件的初步摸索也为进一步在大规模发酵中提高目的蛋白在P.Pastoris的表达水平提供一个参考依据。     

Insect Resistance of Transformed Tobacco Plants with Gene of the Spider Insecticidal Peptide

Tobacco (Nicotiana tabacum)leaves were transformed with Agrobacterium tumefaciens LBA4404 containing the insecticidal peptide gene. Thirty regenerated kanamycin resistant plants were obtained, among which three showed stronger toxicity to Heliothis armigera by feeding experiments. In comparison with feeding of the control plants, mortality of the insects fed on transgenic plants was significantly higher and the growth of the survived insects was remarkably retarded. Results of PCR Southern blot and Northern blot showed that insecticidal peptide gene has been transferred into the genome of these three plants and expressed efficiently to confer the insect resistance of the transgenic plants.     

导入蜘蛛杀虫肽基因的烟草具有抗虫性

用带有杀虫肽基因的农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍ ｅｆａｃｉｅｎｓ）ＬＢＡ４４０４ 转化烟草（Ｎｉｃｏｔｉａｎａ ｔａｂａｃｕｍ ）叶片,共获得３０ 株抗卡那霉素的再生植株． 用这些再生植株对棉铃虫（Ｈｅｌｉｏｔｈｉｓａｒｍ ｉｇｅｒａ）进行毒力测定,有３ 株转杀虫肽基因植株对棉铃虫有较强抗性． 与对照相比,这３ 株转基因烟草的杀虫率可达３０％～４５％ ,并能显著抑制昆虫蜕皮和生长发育,表现出明显的抗虫作用． 以这３ 株为主进行了ＰＣＲ 扩增及Ｎｏｒｔｈｅｒｎ ｂｌｏｔ实验,结果表明杀虫肽基因已插入到这３ 株植株的基因组中并表达出有活性的杀虫肽     

Identification of indole glucosinolate breakdown products with antifeedant effects on Myzus persicae (green peach aphid)

The cleavage of glucosinolates by myrosinase to produce toxic breakdown products is a characteristic insect defense of cruciferous plants. Although green peach aphids ( Myzus persicae ) are able to avoid most contact with myrosinase when feeding from the phloem of Arabidopsis thaliana , indole glucosinolates are nevertheless degraded during passage through the insects. A defensive role for indole glucosinolates is suggested by the observation that atr1D mutant plants, which overproduce indole glucosinolates, are more resistant to M. persicae , whereas cyp79B2 cyp79B3 double mutants, which lack indole glucosinolates, succumb to M. persicae more rapidly. Indole glucosinolate breakdown products, including conjugates formed with ascorbate, glutathione and amino acids, are elevated in the honeydew of M. persicae feeding from atr1D mutant plants, but are absent when the aphids are feeding on cyp79B2 cyp79B3 double mutants. M. persicae feeding from wild-type plants and myrosinase-deficient tgg1 tgg2 double mutants excrete a similar profile of indole glucosinolate-derived metabolites, indicating that the breakdown is independent of these foliar myrosinases. Artificial diet experiments show that the reaction of indole-3-carbinol, a breakdown product of indol-3-ylmethylglucosinolate, with ascorbate, glutathione and cysteine produces diindolylmethylcysteines and other conjugates that have antifeedant effects on M. persicae . Therefore, the post-ingestive breakdown of indole glucosinolates provides a defense against herbivores such as aphids that can avoid glucosinolate activation by plant myrosinases.     

两种凝集素基因在转基因烟草中表达的研究

构建了含尾穗苋凝集素基因(ACA)的cDNA序列和改造后的雪花莲凝集素基因(GNA)的植物表达载体pBACG。在此表达载体中,ACA和GNA基因的表达分别由35S启动子和CoYMV启动子控制。通过农杆菌介导,将ACA和GNA基因转化到烟草中,经卡那霉素筛选获得60株转化再生植株。对PCR检测呈阳性的50株植株进行接蚜虫实验,结果表明,其平均抑虫率达83．9％。Southern blotting分析表明,ACA和GNA基因都已整合到烟草基因组中。Western blotting结果显示这两个基因在不同植株中都可表达其相应的蛋白质,但表达水平不同。部分Western blotting分析呈阳性植株的抗蚜性与T0代相近,达85．3％,说明这两个基因的抗蚜功能可以稳定遗传。     

AtNHX1基因对荞麦的遗传转化及抗盐再生植株的获得

通过农杆菌介导法将拟南芥液泡膜Na /H 反向转运蛋白基因AtNHX1转入荞麦中,在2·0mg/L6-BA、0·1mg/LIAA、1mg/LKT、50mg/L卡那霉素和500mg/L头孢霉素的MS培养基上进行选择培养,从来源于864块外植体的36块抗性愈伤组织中共获得426棵再生植株(转化频率为4·17%)。经PCR、Southern印迹分析、RT-PCR和Northern检测,初步证实AtNHX1基因已整合至荞麦基因组中。用200mmol/L的盐水对转基因植株和对照植株进行胁迫处理6周,转基因植株能够生存,而对照植株死亡。用不同浓度的NaCl溶液处理转基因植株和对照植株,发现Na 及脯氨酸含量在转基因植株中的积累水平显著高于对照植株,而K 的含量在转基因植株中的积累水平低于对照植株。次生代谢产物黄酮类化合物芦丁在转基因植株根、茎和叶片中的含量也比对照植株明显要高。这些结果表明利用基因工程手段提高作物的耐盐性是可行的。     

Major signaling pathways modulate Arabidopsis glucosinolate accumulation and response to both phloem-feeding and chewing insects

Plant responses to enemies are coordinated by several interacting signaling systems. Molecular and genetic studies with mutants and exogenous signal application suggest that jasmonate (JA)-, salicylate (SA)-, and ethylene (ET)-mediated pathways modulate expression of portions of the defense phenotype in Arabidopsis (Arabidopsis thaliana), but have not yet linked these observations directly with plant responses to insect attack. We compared the glucosinolate (GS) profiles of rosette leaves of 4-week-old mutant and transgenic Arabidopsis (Columbia) plants compromised in these three major signaling pathways, and characterized responses by those plants to feeding by two phloem-feeding aphids (generalist Myzus persicae and specialist Brevicoryne brassicae) and one generalist caterpillar species (Spodoptera exigua Hubner). Blocked JA signaling in coronatine-insensitive (coi1) and enhanced expression of SA-signaled disease resistance in hypersensitive response-like (hrl1) mutants reduced constitutive GS concentrations, while blocking SA signaling at the mediator protein npr1 mutant (NPR) increased them. There was no significant impact on constitutive GS contents of blocking ET signaling (at ET resistant [etr1]) or reducing SA concentrations (nahG transgene). We found increased GS accumulation in response to insect feeding, which required functional NPR1 and ETR1 but not COI1 or SA. Insect feeding caused increases primarily in short-chain aliphatic methylsulfinyl GS. By contrast, responses to exogenous JA, a frequent experimental surrogate for insect attack, were characterized by an increase in indolyl GS. Insect performance, measured as population increase or weight increase, was negatively related to GS levels, but we found evidence that other, ET-regulated factors may also be influential. Plant resistance to (consumption by) S. exigua was not related to insect growth because some plant chemistries inhibited growth while others inhibited feeding. These major signaling pathways modulate Arabidopsis GS accumulation and response to both phloem-feeding and chewing insects, often antagonistically; NPR appears to be central to these interactions. Our results indicate that exogenous signal application and plant consumption measures may not provide useful measures of plant responses to actual insect feeding.     

Phloem-based resistance to green peach aphid is controlled by Arabidopsis PHYTOALEXIN DEFICIENT4 without its signaling partner ENHANCED DISEASE SUSCEPTIBILITY1

Green peach aphid (GPA) Myzus persicae (Sülzer) is a phloem-feeding insect with an exceptionally wide host range. Previously, it has been shown that Arabidopsis thaliana PHYTOALEXIN DEFICIENT4 (PAD4), which is expressed at elevated levels in response to GPA infestation, is required for resistance to GPA in the Arabidopsis accession Columbia. We demonstrate here that the role of PAD4 in the response to GPA is conserved in Arabidopsis accessions Wassilewskija and Landsberg erecta. Electrical monitoring of aphid feeding behavior revealed that PAD4 modulates a phloem-based defense mechanism against GPA. GPA spends more time actively feeding from the sieve elements of pad4 mutants than from wild-type plants, and less time feeding on transgenic plants in which PAD4 is ectopically expressed. The activity of PAD4 in limiting phloem sap uptake serves as a deterrent in host-plant choice, and restricts aphid population size. In Arabidopsis defense against pathogens, all known PAD4 functions require its signaling and stabilizing partner EDS1 (ENHANCED DISEASE SUSCEPTIBILITY1). Bioassays with eds1 mutants alone or in combination with pad4 and with plants conditionally expressing PAD4 under the control of a dexamethasone-inducible promoter reveal that PAD4-modulated defense against GPA does not involve EDS1. Thus, a PAD4 mode of action that is uncoupled from EDS1 determines the extent of aphid feeding in the phloem.