灰飞虱Wolbachia群体生物学的遗传特性研究

Ｗｏｌｂａｃｈｉａ是存在于多种昆虫生殖器官的一类共生菌,它可能在宿 主群体中引起细菌质不亲和性而给宿 主带来生殖优势。对灰飞虱体内的Ｗｏｌｂａｃｈｉａｆｊｔｆｄｇｐｗ,ｖ ｇｍ ｐｇｃｆｍｗ ｑｎｎｋｕｄｙｊｒ ｄｏ ｎｕｉ     

棉花转基因技术研究

棉花是一种重要的经济作物,在我国广泛种植。培育转基因棉花被看作是解决产量和生态环境问题最根本和最有效的方式。本文介绍了转基因棉花主要的研究方法,包括转化方法以及转入的基因等,并对转基因棉花的发展趋势作了相关探索。     

超声波对烟草花粉的生物学效应及其诱导外源基因向烟草花粉的转移

用超声波法处理烟草花粉的生物学效应及它诱导ＧＵＳ基因转化烟草花粉,获得了短暂表达的研究结果．单核晚期和双核早中期的烟草游离花粉,置于含０．４ｍ ｏｌ／Ｌ甘露醇的缓冲液中,随着超声强度提高或／和处理时间的延长,对烟草花粉的活力和萌发率具有显著影响．声强０．５Ｗ／ｃｍ ２、时间１０～２０ｍ ｉｎ 是比较理想的参数．将游离花粉与质粒ｐＢⅠ１２１ 混合,以声强为０．５Ｗ／ｃｍ ２ 的脉冲超声波处理１０ｍ ｉｎ, 检测ＧＵＳ基因的平均短暂表达频率（ＴＴＦ％ ）,单核晚期花粉为１８．６％ ,双核早中期花粉为３５．７％ ．对超声转化的不同发育时期的烟草花粉,分别以两条不同途径操作和筛选转基因植株：（１） 单核晚期的花粉：直接进行体外培养、植株再生和筛选,以期获得单倍体转基因植株．在卡那霉素选择培养基上,花粉细胞进行两次或多次分裂后即行停止;（２） 双核早中期的花粉,在体外培养成熟后授粉,收获种子,检测种子中外源基因是否存在．在所收３４１ 粒种子中,没能筛选到卡那霉素抗性植株．就如何筛选超声波转化花粉、获得转基因植株的技术途径进行了讨论．     

Influence of DNA methylation on transgene expression

DNA methylation plays an important role in gene expression in eukaryote. But DNA methylation of transgene usually leads to target gene silencing in plant genetic engineering. In this research, reporter gene b-glu- curonidase (GUS) gene ( uidA ) was introduced into tobaccos via Agrobacterium-mediated transformation method, and the foreign uidA gene became inactive in some transgenic tobaccos. No mRNA of uidA was detected in these plants by Northern blotting analysis, and DNA methylation of promoter region was found. The results indicated that gene silencing might be caused by DNA methylation of promoter.     

植物基因工程中的转基因沉默机制

植物转基因沉默可以发生在染色体DNA、转录和转录后三种不同的层次上,转录水平基因沉默机制涉及DNA甲基化、位置效应、重复序列、同源序列等作用。转录后水平基因沉默机制常用RNA域值模型、异常RNA模型、双链RNA模型、未成熟翻译终止模型等解释。目前没有一种通用的模型可以解释所有的转基因沉默现象,但不同模型从不同方面解释了转基因机制的某些方面。     

p5cs转化水稻细胞系的研究

用基因枪法将豆科植物mothbean（Vigna aconitifolia L．）中的△1-吡咯啉-5-羧酸合成酶（△1-pyrroline-5-carboxylate synthctase，PSCS）基因转化水稻。经PCR扩增和Southernblot分析，证实p5cs基因已整合到水稻细胞基因组中。用250mM NaCl胁迫处理后，发现转基因细胞的脯氨酸含量提高。同时转基因细胞的耐盐性比野生型增强。     

根癌农杆菌法转化烟草的条件探索

 利用含有四环素阻遏蛋白,具有卡娜霉素抗性的烟草种子为实验材料,采用根癌农杆菌介导转化中的叶圆盘法,将外源基因导入烟草愈伤组织,建成可诱导表达细胞质和细胞核CaM/CaM结合多肽的转基因烟草体系.在获得转基因植物的过程中,通过比较影响根癌农杆菌转化频率的各种因素,表明植物材料的选择和培养,农杆菌的培养和稀释,植物材料与农杆菌共培养的程度及转基因植株的筛选条件是影响农杆菌转化效率的重要因素.     

Maize transformation via pollen tube pathway and the inheritance of transgene in progeny

The herbicide-resistant gene als was introduced into maize inbred line Qi319 through pollen-tube pathway. The inheritance of transgene was studied up to 33 generation. Transformation was performed by applying plasmid DNA carrying solution on the severed styles after self-pollination, or just prior to selfpoll/nation. After herbicide screening, PCR and Southern blot analysis, seventeen plants were confirmed positive in TO generation, and sixteen of them were self-bred to construct family to 33 progeny. Through PCR analysis and herbicide screening in offspring, four lines were confirmed following a 3 : 1 Mendelian segregation ratio. In other lines the numbers of positive plants were lower than expected. Therefore, it is necessary to select large population in progeny to produce stable inherited lines when transgene was delivered by pollen tube method.