转基因稻是否会通过基因逃逸导致生态风险?

外源基因从转基因稻逃逸到非转基因稻品种或其野生近缘种有可能导致生态风险。通常转基因逃逸必须满足如下3个条件:(1)转基因稻和非转基因稻或野生近缘种在空间上分布重叠,相邻生长;(2)转基因稻和非转基因稻或野生近缘种在时间上花期相遇;(3)栽培稻与相关近缘野生种在生物学上有一定的杂交亲和性,且杂种后代能正常繁殖。总结分析了栽培稻及含AA基因组近缘种的地理分布、开花习性、种间杂交亲和性以及栽培稻与多年生普通野生稻之间基因流的研究结果,探讨转基因稻的外源基因是否可能逃逸到环境中而导致生态风险。

转基因抗虫水稻秀水134-Bt和非转基因亲本的稻米主要品质性状与淀粉链长分布比较

秀水134-Bt是以‘秀水134'为受体材料,通过根癌农杆菌介导的遗传转化方法导入抗虫基因cry1Ac1获得的转基因纯合品系,本研究对抗虫基因水稻秀水134-Bt与其原亲本‘秀水134'稻米的品质性状、理化特性及支链淀粉链长分布进行了比较分析。结果发现:转基因水稻秀水134-Bt与非转基因亲本‘秀水134'非常相似,稻米主要品质性状包括外观品质、碾磨品质、直链淀粉含量、胶稠度、淀粉黏滞性及支链淀粉的链长分布等食用品质方面基本相同,说明在水稻遗传转化操作过程中,TDNA插入并未显著改变原亲本稻米的主要品质特性。

农杆菌转化花粉愈伤组织获取纯合的转基因水稻植株

应用农杆菌介导法成功地将玉米转座子 Ds导入粳稻 (Oryza sativa L.subsp.japonica)中花 11的花粉愈伤组织中 ,基因转化以对除草剂 PPT有抗性的 Bar基因和潮霉素抗性基因 H pt为选择标记 .共获得了 18个独立的转基因绿苗 ,其中单倍体 11株 ,二倍体 7株 .转基因植株均抗除草剂 BASTA.考查了二倍体植株种子后代 (T1)对 BASTA的抗性 ,7个株系的所有植株均抗 BASTA,而未发生感抗分离 ,表明外源基因在转基因植株中是纯合的 .PCR和 Southern blotting的研究支持上述结果 .

山东大育出多抗转基因夏稻新品系

由山东农业大学温孚江教授主持的国家转基因植物研究与产业化专项“黄淮稻区优质多抗超级夏稻转基因新品种(组合)选育”课题研究，选育出的6个多抗转基因夏稻新品系和一批农艺性状良好、抗病、抗虫性强、遗传稳定的纯合株系通过田间验收，

转Bt基因水稻对主要非靶标昆虫的生态安全性研究进展

Bt基因是世界上转基因植物生物工程研究和应用最多的基因。转Bt基因水稻对二化螟、三化螟、稻纵卷叶螟等鳞翅目害虫具有很强的控制效果,其商业化种植推广是国内外关注的焦点问题。概述了Bt水稻研究概况的基础上,主要针对Bt水稻对稻田非靶标昆虫的影响效应进行综述,并对Bt水稻的发展前景及其对非靶标昆虫的安全性研究进行展望。

转基因大米明年摆上中国餐桌？

种种迹象表明，到2005年，转基因稻米可能获得准生证，进而走上餐桌，中国有可能成为世界上第一个大面积种植转基因口粮的国家。但国内外一些人士担心，其中仍然潜藏着风险。

水稻中细菌nhaA基因的过表达促进水稻的耐盐性和耐旱性

编码Na^＋／H^＋反向载体的大肠杆菌nhaA基因在体内离子的自动平衡中起关键的作用。我们将细菌性nhaA基因转入水稻（Oryza sativa L．ssp．japonica）中，并在转基因稻中检测到高水平的表达。在受到盐胁迫和干旱胁迫条件下，转基因稻的发芽率，生产量，每株产量都优于对照品系。而且，在受到盐胁迫和干旱胁迫条件下，转基因稻的Na含量和脯氨酸含量都高于对照品系，这说明有激活脯氨酸的生物合成调控或者促进nhaA的过表达。比较了过表达nhaA的转基因稻和过表达编码鸟氨酸-△-氨基转移酶的拟南芥（Arabidopsls）△—OAT间的耐盐性和耐旱性。在高盐浓度条件下，含nhaA基因的转基因植株长势比含△-OAT基因的好；同时，在干旱条件下，同样也是含nhaA基因的转基因植株长势比含△-OAT基因的好。

盐胁迫对黄华占和中优36水稻种萌芽的比较研究

为了研究不同品种水稻对盐胁迫的适应性,对黄华占和中优36两个杂交水稻在盐胁迫下的发芽率、淀粉酶、超氧化物歧化酶、硝酸还原酶、过氧化氢酶和过氧化物酶6个生理生化指标的动态变化进行比较研究,结果表明:(1)中优36的发芽率随胁迫浓度上升而极显著地下降,黄华占的发芽率则受影响很小;(2)在萌芽过程中,随着胁迫浓度的上升,两种水稻的淀粉酶和过氧化氢酶活性均显著下降,硝酸还原酶活性表现为先上升后下降;(3)盐胁迫下超氧化物歧化酶和过氧化氢酶的活性在黄华占中表现得更敏感,淀粉酶和硝酸还原酶活性和发芽率在中优36中表现得更敏感。

转基因水稻与野生稻(Oryza nivara Sharma et Shastry)杂交后代种子萌发率

种子休眠性是野生植物重要的适应性状,通过种子萌发实验可以分析种子休眠性强弱.通过人工杂交获得转抗虫基因栽培稻与一年生普通野生稻三种组合的杂种,对杂种的F3代和F4代种子采用直接萌发、打破休眠后萌发、埋土15 d和30 d 4种不同处理来检测种子活力和萌发率.结果显示转基因杂种后代种子表现出较强的休眠性,转基因对种子活力和休眠性没有明显的影响,种子休眠性有随种子世代的增加而逐渐减弱的趋势,提示水稻转基因逃逸后有在野生稻群体中宿存和扩散的可能性,但这种可能性可能会随世代增加而下降.这为进一步研究水稻转基因逃逸风险提供了参考.

Transfer of Lysine-rich Protein Gene into Rice and Production of Fertile Transgenic Plants

Lysine-rich protein gene (lys) was cloned from Psophocarpus tetragonolobus (L.) DC. A plant expression plasmid was constructed and lys gene was under the control of maize ubiquitin promoter which is the highest efficient monocotyledon promoter. The plasmid was introduced into rice embryogenic calli by microprojectile bombardment. The regenerated fertile plants were obtained by effective selection for hygromycin B resistance. Genomic PCR and Southern blotting analyses showed that the lys gene has been integrated into rice genome. Simultaneously, the results of GUS histochemical assay demonstrated that gus report gene is also expressed in leaves, stems and roots of the transgenic rice plants. Data analysis showed that lysine content in most of the 11 transgenic plants is differently improved, and in one of them increased by 16.04%.

Transformation of Pea Lectin Gene and Parasponia Haemoglobin Gene into Rice and Their Expressions

Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogenase from oxygen in symbiotic nitrogen-fixing nodules. In order to extend the host range of the rhizobial bacteria and to make them fix nitrogen in non-legumes, pea lectin gene (pl) and Parasponia hemoglobin gene ( phl,) have been constructed into a plant expression vector (pCBHUL) and the vector pCBHUL was introduced into rice calli from immature young embryos by particle bombardment. After the calli were regenerated into plantlets on the resistant-selecting media containing hygromycin, they were identified by PCR and Southern blot hybridization. It was indicated that the pi and phb genes were integrated into nucleic genome of the transformed rice plants. GUS activity and the product of the pi gene were determined by GUS staining, Western blot and in situ hybridization at translational level. Eighteen out of 40 plants resistant to hygromycin were positively identified by PCR analysis with the rate of 45%. The pi gene was expressed in 3 out of 18 plants with 17% and 7.5% in 40 plants. The results may provide a clue for exploring whether Rhizobium leguminosarum by. viceae could extend its host range and make the transgenic rice plants have the possibility of being symbiotic, or associative to nitrogen fixation.

Photosynthetic Characteristics of Transgenic Rice Plants Overexpressing Maize Phosphoenopyruvate Carboxylase

用转PEPC、PPDK、NADP_ME、PEPC +PPDK 双基因水稻 (OryzasativaL .)及原种为材料 ,以光合酶活性、饱和光合速率及PSⅡ光化学效率 (Fv/Fm)为指标 ,研究了转PEPC基因水稻的光合生理特征。结果如下 :转PEPC基因水稻PEPC活性比原种提高 2 0倍 ;饱和光合速率比原种高 5 5 % ;用高光强或人工光氧化剂甲基紫精 (MV)处理后 ,与原种相比 ,转PEPC基因水稻光化学效率下降较少 ,证明其耐光抑制、耐光氧化能力增强 ,测定其光合日变化看出 :在 1d中不同时间 ,转PEPC基因水稻的光合速率均高于原种 ,且与PEPC活性的日变化有相似的趋势。上述结果为转PEPC基因水稻的生理机制和育种研究提供了依据和途径。

Agrobacterium _mediated Transformation of Rice with Help of Bombardment

Oryza sativa L. ssp. japonica cv. Zhonghua 8, which is recalcitrant to infection of Agrobacterium tumefaciens (Smith et Townsend) Conn strain EHA105 with ordinary binary vector pCambia 1301, was transformed through Agrobacterium-mediated transformation with help of bombardment. The transformation efficiency can be raised greatly. Single copy of gene insertion in the genome of transgenic rice plants was proved by Southern analysis and the expression of GUS gene was observed. GUS gene and hygromycin-resistant gene show 3:1 segregation in progenies of the transgenic rice plants.

Characteristics of CO_2 Exchange and Chlorophyll Fluorescence of Transgenic Rice with C_4 Genes

The responses of photosynthesis of phosphoenopyruvate carboxylase (PEPC), pyrurate dikinase (PPDK), NADP-malic enzyme (NADP-ME) and PPDK+PEPC transgenic rice (Oryza saltiva L.) plant to light, temperature, CO 2 and the characteristics of chlorophyll fluorescence under photoinhibition conditions were studied. The results were as follows: 1. The light-saturated photosynthetic rates of transgenic rice plants were higher than that of wild type, in which the light-saturated point of PEPC and PPDK+PEPC transgenic rice plants was 200 μmol·m -2·s -1 higher than that of untransformed rice and the light-saturated photosynthetic rates were 51.6% and 58.5% respectively. The carboxylation efficiency of PEPC transgenic rice plant increased by 49.3% and the CO 2 compensation point decreased by 26.2% than that of untransformed rice. Under high temperature (35 ℃), the photosynthetic rate of PEPC transgenic rice plant was higher over 17.5% than that of untransformed rice. 2. On the 8th day after photoinhibition treatment, the PSⅡ photochemical efficiency (F v/F m) and photochemical quenching (qP) of PEPC and PPDK+PEPC transgenic rice plants decreased by about 20%-30% while the non-photochemical quenching (qN) increased by approximately 30%. But F v/F m and qP of untransformed rice decreased by over 50% while qN increased by less than 10%. The result suggested that transgenic rice plants were more tolerant to photoinhibition.

Main Agronomic Characters and Grain Quality of Rice Blast Resistance Gene Pi-d2 Transgenic Rice

[Objective] The aim of this study was to provide metabolic evidence for the analysis of the ecological and safety assessment of Pi-d2-transgenic rice.[Method] The main agronomic characters of Pi-d2-transgenic rice were observed in field experiment and the grain chemical characters and amino acid content were measured.[Results] Introduction of foreign gene Pi-d2 resulted in stably hereditable variation in agronomic characteristics in the descents.Most of the transgenic lines grew normally and orderly.Compared with the control（wild type plants）,about half of transgenic plants showed an increased or reduced plant height.There was no observable difference between transgenic plants and controls in tiller number,length of panicle,panicles per plant,seed-setting rate and 1 000-grain weight.Total amino acid content in transgenic rice was reduced,while the starch content,GC and GT were not altered in comparison with the control.[Conclusion] Introduction of foreign gene Pi-d2 has remarkable influence on plant height,while little on grain chemical characters.

Differences in Ecological Fitness Between Bt Transgenic Rice and Conventional Rice Under Insect-infestation Pressures

[Objective] This study aimed to improve density and practicality of the ge- netic map of sunflower （Helianthus annuus L.） by adding some SSR markers. [Method] A total of 123 F8 RILs populations derived from a cross between PAC-2 and RHA-266 were selected as the materials, and a total of 300 pairs of SSR primers were used to screen polymorphic markers between the parents and some of their RILs, and finally 51 pairs of the primers producing polymorphic patterns were selected to construct the genetic map of the RILs populations. [Result] Nineteen pairs of SSR primers did not generate polymorphic patterns or any bands, and 32 SSR pairs showed polymorphism. Thirty-five alleles which distributed in the 15 link- age groups of the maps were detected. The new map covered a total length of 2 914.5 cM, 7.5 cM longer than that of the original map. The average marker interval is 8.1 cM replacing original 9.0 cM. [Conclusion] This study provided reference for genetic map integration and molecular marker assisted selection of sunflower.

Expression of Bt Protein in Transgenic Pest-resistant Rice

[Objective] The aim of this study was to study on expression of Bt protein in transgenic pest-resistant rice. [Method] Enzyme-linked immunosorbent assay （ELISA） was used to measure Bt protein expression in different tissues of transgenic pest-resistant rice at same growth stage. [Result] Absolute content of Bt protein from high to low was as follows： leaves 〉 immature seeds and glumes 〉 roots 〉 stems in different tissues of transgenic rice in grain-filling stage; Bt protein content of trans- genic rice changed a little in different growth stages （including tillering stage, booting stage, and grain-filling stage）; in general, its level declined a little in later growth stage, but the resistibility would not be influenced significantly. [Conclusion] The ex- periment is significant for pest prevention and transgenic rice breeding.

Physiological Character and Gene Mapping in a New Green-revertible Albino Mutant in Rice

A green-revertible albino mutant-Qiufeng M was found from the japonica rice （Oryza sativa L. ssp. japonica） Qiufeng in the field. The first three leaves of the mutant were albino with some green. The leaf color became pale green since the fourth leaf and the glume had the same phenomenon as the first three leaves. The measuring data of the pigment content confirmed the visually observed results. It truly had a remarkable changing process in the leaf color in Qiufeng M. Comparison of the main agronomic characters between Qiufeng and Qiufeng M indicated that the neck length and grain weight showed significant difference at the 1% level, and other characters were not different. Genetic analysis showed that the green-revertible albino trait was controlled by a single recessive nucleic gene. Using 209 recessive mutant individuals in the F2 population derived from the cross Pei＇ai 64S × Qiufeng M, a gene, tentatively named gra（t）, was located between the SSR markers of RM475 and RM2-22 on the long arm of chromosome 2. The genetic distance were 17.3 cM and 2.9 cM respectively.

Overexpression of glutamine synthetases confers transgenic rice herbicide resistance

Glutamine synthetase (GS, E.C.6.3.1.2) is a key enzyme involved in the assimilation of inorganic nitrogen in higher plants and gram-negative microorganisms. GS is the targeting enzyme of a herbicide phosphinothricin (PPT) or Basta. In order to generate PPT-resistant transgenic rice via overexpression of GS, we constructed a plant expression vector p2GS harboring two different isoenzymes GS1 and GS2 cDNAs under the control of constitutive promoters of rice Act1 and maize Ubiquitin(Ubi) genes. The p2GS was introduced into rice genome by Agrobacterium-mediated transformation and confirmed by PCR and Southern blot hybridization. GS-transgene expression was first detected by Northern blot analyses. Results from Basta test indicated that GS-transgenic plants can tolerate as high as 0.3% Basta solution. In addition, our results also demonstrated that GS overexpression conferred transformed rice calli PPT resistance. Thus, GS cassette can serve as a selective marker gene instead of bar cassette for selection of PPT transformants.

Research on Frequency of Exogenous Gene Flow from Marber-free Insect-resistant Transgenic Rice to Conventional Rice Varieties

[Objective] This study aimed to investigate the frequency of exogenous gene flow to non-transgenic conventional rice cultivars and assess the potential risks of marker-free of insect-resistant transgenic rice to agricultural ecological environment. [Method] Insect-resistant transgenic rice variety HUAHUI No.1 was planted as the experimental material and surrounded by several non-transgenic conventional rice cultivars. F1 non-transgenic rice seeds were collected according to different distances and identified by using PCR technology, the frequency of exogenous gene flow from insect-resistant transgenic rice to non-transgenic conventional rice cultivars was counted and analyzed. [Result] The average frequency of exogenous Bt gene flow to P13381 and CHUNJIANG063 was 0. Transgene flow occurred to varying degrees from insect-resistant transgenic rice HUAHUI No.1 to several non-transgenic rice lines including HEX122-2, TIANXlANG, MINGHUI63 and Pl157, with the maximum average gene flow frequency of 0.875%. The frequency of gene flow was gradually reduced with the increase of distance, and the average transgene flow frequency de- creased to 0 in all the sampling points 7 m away from transgenic rice material. [Conclusion] This study revealed that the exogenous gene flow frequency of insect-re- sistant transgenic rice variety HUAHUI No.1 was very low, leading to very small risk to the eco-environment. Rational distribution in the field for physical isolation, keeping the appropriate distance and scientific farming arrangement to avoid the synchronization of flowering can effectively control the exogenous gene flow from transgenic rice and reduce he ecological risks caused by transgene escape.