Influence of alloplasm on resistance to wheat scab

Using alloplasmic wheat as test materials, the genetic effect of cytoplasm on wheat scab resistance was studied by three methods including the determination of resistance of explant calli toGibberella zeae toxin, the identification of inoculating single fixed position and the identification of field resistance. The results showed that among “the homonucleo-heterocytoplasmic lines”, resistance of calli toG. zeae toxin was different; the difference of cytoplasmic effect among different nucleoplasm combinations showed certain nucleoplasm interaction relation. Resistance of hybrid F₁ plants of reciprocal cross between alloplasmic line and disease-sensitive wheat variety to wheat scab was of clear difference. Hybrid F₁ of reciprocal cross betweenAe. ventricosa cytoplasmic wheat and disease-sensitive or -resistant wheat variety all exhibited fine resistance effect of alloplasm. Compared with general common wheat variety, most alloplasmic wheats tested have stronger resistance. A few selected lines havingAe. ventricosa cytoplasm have a strong and stable resistance to scab. They can be a finer new resistant source.     

Establishment of a genetic transformation system for maize inbred P9-10

It was found that the supplement of 10 -4 mol/L AgNO3 in N6 medium enhanced the induction of type Ⅰ embryogenic calli from immature embryos of maize inbred P9-10. After high-osmotic treatment, the induced calli was taken as transformation recipient to be bombarded with plasmid pMG6 carrying synthetic Bt gene by PDS-1000/He genegun. A total of 14 resistant calli were obtained after screening subsequently on the mediums with gradually increasing selective pressure. 10 plants were regenerated from the resistant calli on 3 different induction media, and 8 out of the 10 regenerated plants were confirmed to be integrated with Bt gene by PCR and Southern blotting analysis. Results of ELISA showed that the Bt-protein content in the leaves of the transgenic plants varied between 20-200 ng/g fresh weight.     

农杆菌介导的胆碱脱氢酶基因(betA)转化小麦及影响转化效率的因素

用LBA4404／pCDH，Agl 1／pUNN2和Ag;P(无质粒)3种菌株分别转化小麦品种济南177、99P、核生3号幼胚诱导的愈伤组织以及济南177的幼胚．其中以胚性愈伤组织为外植体，获得了转基因植株．PCR和PCR-Southem分析证实转化植株中包含了外源基因．通过染色体分析，发现胚性愈伤组织在农杆菌LBA4404侵染后形成的染色体削减比经Agl1侵染和未经感染的对照形成的染色体削减程度更大，甚至发现较多的染色体断片．分析了农杆菌菌株，材料的基因型，外植体类型，培养时间和温度以及筛选的时间和周期对于转化效率的影响．     

A transgenic wheat with a stilbene synthase gene resistant to powdery mildew obtained by biolistic method

Stilbene, a kind of phytoalexin, plays an important role in resistance to fungal and bacterial infection in plants. It strongly inhibits the growth of fungi and sprout of spore. Stilbene synthase gene (Vst1) obtained from grapevine has been transferred into common spring wheat Jinghong 5 by using the biolistic transformation method. Five transgenic plants (T₀) were obtained from the bombarded 2014 immature embryos. One immune plantlet and 3 plantlets with mid-resistance to powdery mildew were identified from the transgenic plants of T₃ generation which came from 2 T₀ transgenic plants.     

Studies of Improving the Frequency of Indica Rice Transformation by Biolistic Bombardment

In order to improve the frequency of indica rice transformation by biolistic bombardment,suitable culture conditions for embryonic calli,an optimal selection scheme for resistant calli and seedling,and optimum bombardment parameters a investigated by using 14 commercially important indica rice cultivars.The main results show that the CC medium with 36g/L mannitol is a scheme subculture medium in which the browning of indica rice calli can be mitigated significantly;The concentration of 30-40mg/L Hyg or 150-200mg/L G418 or 10-20mg/L Basta is suitable for selection of resistant calli;The transformation parameters of 100μg gold powder absorbing 0.2μg DNA per shot and 900 psi helium pressure and 6 cm bombardment distance and bombarded twice for each plate give the best result;Keeping the target calli on osmotic medium containing 60g/L mannitol from 12-24h before bombardment to 24-48h after it can increase the efficiencies of transformation.Furthermore,some transgenic indica rice plants are obtained using this optimized transformation system.     

Transformation of japonica rice with<Emphasis Type="Italic">RHL</Emphasis> gene and salt tolerance of the transgenic rice plant

Overexpression of the yeastHAL2 gene increases salt tolerance of yeast and plant. RiceHAL2-like (RHL) gene was introduced into ajaponica rice cultivar HJ19 withAgrobacterium tumefaciens-mediated transformation. Transgenic plants in R₀ generation were selected on the principle of GUS-positive,RHL gene PCR-positive and normal growth. Hygromycin-resistant plants of some transgenic lines in R₁ generation increased salt tolerance during the seedling and booting stage, being less damaged in the cytomembrane and stronger in leaf tissue viability under salt stress during booting period. Southern analysis of transgenic lines tolerant to salt in R₁ generation showed that theRHL gene expression cassette had been successfully integrated into rice genome. Moreover, gene engineering breeding methodology and really salt-tolerant rice cultivar were discussed.     

Integration and inheritance stability of foreignBt toxin gene in the bivalent insect-resistant transgenic cotton plants

Genetic and expressional stability of Bt toxin gene is crucial for the breeding of insect-resistant transgenic cotton varieties and their commercialization. Genomic Southern blot analysis of R₃, R₄ and R₅ generations of bivalent transgenic insect-resistant cotton plants was done in order to determine the integration, the copy number and the inheritance stability of Bt toxin gene in the transgenic cotton plants. The results indicated that there was a 4.7 kb positive band in the Southern blot when the genomic DNA of the bivalent transgenic insect-resistant cotton plants and the positive control (the plasmid) were digested with HindⅢ respectively. This result proved that the Bt toxin gene had been integrated into the genome of the cotton in full length. There is only one XhoⅠ restriction site in the Bt toxin gene. Southern blot analysis indicated that many copies of Bt toxin gene had been integrated into the genome of the cotton when the genomic DNA of transgenic plants was digested with XhoⅠ. Among them, there were four copies (about 17.7, 8, 5.5 and 4.7 kb in size) existing in all the tested plants of ₃, R₄ and R₅ generations. The preliminary conclusion was that there were more than four copies of Bt toxin gene integrated into the genome of the cotton, among them, more than one copy can express and inherit steadily. This result provides a scientific basis for the breeding of the bivalent insect-resis- tant transgenic cotton plants and its commercialization.     

Development of Triticum aestivum-Leymus racemosus ditelosomic substitution line 7Lr#1S（7A） with resistance to wheat scab and its meiotic behavior analysis

Leymus racemosus is highly resistant to wheat scab （Fusarum head bright）. The transfer of scab resistant gene from L. racemosus to Triticum aestivum is of great significance for broadening the base of wheat resistance. In the present study, the pollen of T. aestivum-L, racemosus monosomic addition line with scab resistance was treated by irradiation with 1200 R ^60Co-γ-rays prior to pollinating to emasculated wheat cv. Mianyang 85-45. Nine plants with a telocentric chromosome 7Lr#1S were observed in M1, and one ditelosomic substitution line 7Lr#1S was selected from selfcrossing progenies and confirmed by chromosome C-banding and GISH. Furthermore, a co-dominant EST-SSR marker CINAU 31 was employed to identify this substitution line. A pair of chromosome 7A of common wheat were found to be replaced by a pair of telocentric chromosome 7Lr#1S, and further investigation showed that chromosome configuration of the substitution line at MI of PMCs after GISH was 17.50Ⅱ^w ＋ 2.19Ⅱ^w ＋ 0.42Ⅱ^7Lr#1S ＋ 1.08 Ⅰ^7Lr#1S ＋ 0.69 Ⅰ^w. Two telocentric chromosomes paired as a bivalent in 59.7% of PMCs. Abnormal chromosome behaviors of telocentric chromosomes were observed in part of PMCs at anaphase I and telophase I, including the moving of two telocentric chromosomes to the same pole, lagging and earlier separation of their sister chromatid. All these abnormal behaviors can be grouped into three distinct types of tetrads according to different numbers of 7Lr#1S in their daughter cells and various micronucleus in some tetrads. However, due to the high transmission frequency of the female and male gametes with a 7Lr#1S, 84% of the selfcrossing progeny plants had ditelosomic substitution. The substitution line showed high resistance to wheat scab in a successive two-year test both in the greenhouse and field; hence, the line will be particularly valuable for alien gene mapping, small fragment translocation induction and telosomic cytological behavior analysis.     

影响根癌农杆菌转化水稻频率的因素研究

根癌农杆菌与来自水稻成熟种子的愈伤组织共培养,将外源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,表明在转化过程中酚类化合物和单糖的加入使农杆菌的转化频率提高了０．９％～１７．４％．在共培养时农杆菌的稀释方式也是影响农杆菌转化频率的重要因素     

Transgenic rice homozygous lines expressing GNA showed enhanced resistance to rice brown planthopper

Mature seed-derived calli from two elite Chinese japonica rice (Oryza sativa L.) cultivars Eyi 105 and Ewan 5 were co-transformed with two plasmids, pWRG1515 and pRSSGNA1, containing the selectable marker hygromycin phosphotransferase gene (hpt), the reporter β-glucuronidase gene (gusA) and the snowdrop (Galanthus nivalis) lectin gene (gna) via particle bombardment. 61 independent transgenic rice plants were regenerated from 329 bombarded calli. 79% transgenic plants contained all the three genes, revealed by PCR/Southern blot analysis. Western blot analysis revealed that 36 out of 48 gna-containing transgenic plants expressed GNA (75%) at various levels with the highest expression being approximately 0.5% of total soluble protein. Genetic analysis confirmed Mendelian segregation of transgenes in progeny. From the R2 generations whose R1 parent plants showing 3:1 Mendelian segregation patterns, we identified five independent homozygous lines containing and expressing all the three transgenes. Insect bioassay and feeding tests showed that these homozygous lines had significant inhibition to rice brown planthopper (Nilaparvata lugens, BPH) by decreasing BPH survival and overall fecundity, retarding BPH development and declining BPH feeding. These BPH-resistant lines have been incorporated into rice insect resistance breeding program. This is the first report that homozygous transgenic rice lines expressing GNA, developed by genetic transformation and through genetic analysis-based selection, conferred enhanced resistance to BPH, one of the most damaging insect pests in rice.     

Genetic transformation of calli from maize and regeneration of herbicide-resistant plantlets

The herbicide-resistant geneals ofArabidopsis thaliana has been transferred into embryonic calli of maize by microprojectile bombardment. We have obtained chlorsulfuron-resistant calli and regenerated plantlets through selection by herbicide chlorsulfuron. The results of PCR analysis and Southern blotting indicate that geneals has been transferred into some plantlets. The test of spraying chlorsulfuron indicated that the transgenic plantlets had favorable herbicide-resistant trait. The purpose of the research was to obtain chlorsulfuron-resistant transgenic maize and hope that this kind of high efficient herbicide could be widely used in rotation soil of wheat and maize. In addition, through spraying herbicide, we could eliminate the hybrid plants and thereby increase the purity of F1 seeds.     

抗除草剂旱稻转基因植株的获得

以旱稻丹粳旱５－５５、６－２４、６－３７的悬浮细胞及未成熟胚为受体材料，采用基因枪法将含ＢＡＲ基因的ｐＤＭ３０２质粒ＤＮＡ导入旱稻细胞中，经ＰＰＴ筛选获得抗性愈伤组织，筛选出的愈伤组织在分化培养基上再生出完整的旱稻转基因植株。Ｓｏｕｔｈｅｒｎ分子杂交分析表明，外源ＢＡＲ基因已整合到水稻基因组内，抗除草剂试验结果表明，转化植株对０．０１％Ｂａｓｔａ（有效成分为ＰＰＴ）有一定程度的抗性，说明外源ＢＡＲ     

大麦黄矮病毒（BYDV）外壳蛋白基因在小麦原生质体中的稳定转化

实验采用ＰＥＧ介导法转化小麦，用ＧＵＳ基因作为标志，用荧光法测定Ａｃｔｌ－ＧＵＳ、Ｅｍｕ－ＧＵＳ、３５Ｓ－ＧＵＳ三种质粒转化小麦细胞后的瞬间表达强度，以比较Ａｃｔｌ、Ｅｍｕ、３５Ｓ三种启动子在小表中的表达强度．结果表明，Ａｃｔｌ和Ｅｍｕ的强度大致相等，均比３５Ｓ强．采用Ｅｍｕ为启动子带ＢＹＤＶＣＰ基因的质粒和经改造过的Ａｃｔ１为启动子带有抗潮霉素选择标记基因的质粒共转化小麦“济南１７７”的原生质体．转化６ｄ后，用潮霉素进行筛选，最后得到两块抗潮霉素的愈伤组织，转化后４个月，经ＰＣＲ检测，证明ＣＰ基因已整合进一块愈伤组织的细胞基因组中．     

农杆菌介导的DREB1A基因转化多花黑麦草及其转化体系的优化

采用携带卡那霉素抗性基因nptII和GUS基因的ubiquitin启动子驱动的表达载体pBI121／DREB1A的根癌农杆菌AGL1, 对多花黑麦草幼胚来源的胚性愈伤组织进行了遗传转化,并优化了各种影响因素。胚性愈伤组织经根癌农杆菌感染和共培养后,用50mg／L巴龙霉素筛选抗性愈伤组织,待抗性愈伤组织在IB分化培养基上分化成苗后用25mg／L卡那霉素进一步筛选再生植株, 获得了部分抗性植株。抗性植株的总DNA用DREB1A基因的特异引物进行PCR检测,转化频率为2.14％,PCR-Southern blot进一步验证了转化植株基因组中含有该外源基因。各种影响转化效率因素的优化实验表明,当转化时菌液浓度的OD600为2.0、侵染时间为1h、共培养时间为2d、共培养温度为21℃及在共培养期间使用乙酰丁香酮等,均可明显提高转化频率。     

应用农杆菌介导法的多年生黑麦草遗传转化研究

以草坪型多年生黑麦草Lolium perenne L.成熟种子为外植体,经过愈伤组织诱导和植株再生研究,建立了该草种的遗传转化体系,并成功地应用农杆菌介导法将克隆自辽宁碱蓬的甜菜碱醛脱氢酶基因(BADH)转移进多年生黑麦草,获得的转基因株系Gsc-LP5通过PCR检测证明了目的基因的存在,通过叶片离体检测法证明了作为检测基因随同质粒一同转入的抗潮霉素基因的表达,通过盆栽耐盐试验证明了转基因植株具有较强的耐盐能力.     

小麦遗传转化方法研究进展

目前小麦遗传转化尽管有多种方法,但转化效率仍然很低,一个重要原因是遗传转化方法尚不成熟,因此建立合适的转化方法是小麦遗传转化成功的关键.本文综述了小麦基因枪转化、农杆菌介导的遗传转化和花粉管通道法等几种重要遗传转化方法研究的最新进展,分析了各种方法的基本原理、优缺点及其影响因素.最后对小麦遗传转化研究中存在的主要问题进行了总结,并展望今后的研究重点与发展趋势.     

Molecular cytogenetic analysis of Triticum aestivum-Leymus racemosus reciprocal chromosomal translocation T7DS·5LrL/T5LrS·7DL

In order to induce chromosome translocation between wheat chromosomes and chromosome 5Lr of Leymus racemosus, the mi- crosporocytes during meiosis of T. aestivum-L. racemosus disomic addition line DA5Lr were irradiated by 60Co γ-rays 800 R (100 R/min). Before flowering, the treated spikes were emasculated and bagged. After 2-3 d, the emasculated flowerets were pollinated using pollens from T. aestivum cv. Chinese Spring. One plant with two translocation chromosomes involved in both the long and short arm of...     

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.     

Ubi1 intron-mediated enhancement of the expression of Bt cry1Ah gene in transgenic maize （Zea mays L.）

The cry1Ah gene was one of novel insecticidal genes cloned from Bacillus thuringiensis isolate BT8. Two plant expression vectors containing cry1Ah gene were constructed. The first intron of maize ubiqutinl gene was inserted between the maize Ubiquitin promoter and cry1Ah gene in one of the plant expressing vectors （pUUOAH）. The two vectors were introduced into maize immature embryonic calli by microprojectile bombardment, and the reproductively plants were acquired. PCR and Southern blot analysis showed that foreign genes had been integrated into maize genome and inherited to the next generation stably. The ELISA assay to T1 and T2 generation plants showed that the expression of CrylAh protein in the construct containing the ubil intron （pUUOAH） was 20% higher than that of the intronless construct （pUOAH）. Bioassay results showed that the transgenic maize harboring cry1Ah gene had high resistance to the Asian corn borers and the insecticidal activity of the transgenic maize containing the ubil intron was higher than that of the intronless construct. These results indicated that the maize ubil intron can enhance the expression of the Bt cry1Ah gene in transgenic maize efficiently