两个反义基因在番茄工程植株中的生理抑制效应分析

用番茄乙烯形成酶（ＥＦＥ）和多聚半乳糖醛酸酶（ＰＧ）反义ｃＤＮＡ转化番茄子叶,获得两个转基因系统。分别比较了两个基因系统果实和叶片的乙烯生成速率、果实中ＥＦＥ酶活性和果胶酶活性,表明反义ＥＦＥ基因在番茄工程植株中能显著抑制ＥＦＥ酶活性和乙烯生成;反义ＰＧ基因则主要是抑制其ＰＧ酶活性。     

植物Dof基因家族功能研究进展

Dof(DNA-binding with one finger)蛋白是植物特有的一类转录因子,在植物生长发育过程中起着重要的作用。在其N-末端有一个52氨基酸残基组成的高度保守的C2-C2单锌指结构,称为Dof保守域,能够特异性的识别植物启动子序列中的AAAG/CTTT作用元件,从而激活或抑制植物基因的表达;其C-末端的转录调控结构域,氨基酸序列较为多变,不具有保守性,是Dof蛋白在植物中功能多样性的基础;同时Dof蛋白也具有和蛋白相互作用的功能。在过去的十几年里,大量的Dof基因被克隆鉴定或从基因组数据库中预测出来,Dof蛋白在植物生长发育中的作用也受到更多关注。本文就Dof转录因子的特点,各物种中已经报道的Dof转录因子的数目、系统进化关系和分类及其生物学功能的进展进行了综述。     

转ipt和反义ACO基因番茄的叶片衰老相关特性

以ipt和反义ACO转化的两类转基因番茄纯系为材料,研究在植株不同生长发育阶段,不同叶位中,与叶片衰老相关的生理生化指标.结果表明:两类基因导入番茄后,均可增强内源iPA和IAA表达水平,增加或保持番茄叶片的叶绿素含量、提高光合效率,进而明显地延缓植株的叶片衰老,提高单株果实产量.但它们调控叶片衰老的途径不同,ipt主要通过提高CTK的水平延缓叶片衰老,而反义ACO则主要是通过抑制乙烯生成,间接提高IAA的水平来实现.     

雪花莲外源凝集素基因转化番茄

The plasmid pRSSGNA1 carried a snowdrop lectin gene (Galanthus nivalis agglutinin, GNA) under the drive of RSs-1 promoter, were successfully transferred into three tomato (Lycopersicon esculentum Mill.) cultivars, “C8”,“A39” and “A53” via Agrobacterium-mediated transformation. Regenerated plantlets were obtained from cotyledons after preculture, shoot inducing culture and root inducing culture. Transgenic tomato plants were confirmed by the kanamycin-resistant experiment, PCR analysis and Southern blot. The preliminary results from bioassay demonstrated significant resistance of the transgenic plants to aphid (Myzus persicae Sulzer) larvae. The inheritance of selective marker gene (NPTⅡ) in 3 transgenic tomato plants is in the model of the simple Mendel's fashion in progenies of the selfing generation.     

Ectopic Expression of the Tomato <Emphasis Type="Italic">Mi-1</Emphasis> Gene Confers Resistance to Root Knot Nematodes in Lettuce (<Emphasis Type="Italic">Lactuca sativa</Emphasis>)

The full genomic region of the root knot nematode (Meloidogyne spp.) resistance gene Mi-1 was cloned from tomato and transformed into lettuce to investigate its function in a heterologous system. Transgenic lettuce lines containing the Mi-1 gene were developed using Agrobacterium-mediated transformation. Ectopic expression of the Mi-1 gene was observed in transgenic lines, and resistance to root knot nematode was improved.     

A Novel Cytoplasmic Isopentenyl Diphosphate Isomerase Gene from Tomato (<Emphasis Type="Italic">Solanum lycopersicum</Emphasis>): Cloning,Expression, and Color Complementation

Isopentenyl diphosphate isomerase (IPI; EC5.3.3.2) catalyzes isomerization between isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), both of which are essential precursors for terpenoid biosynthesis. A novel gene encoding isopentenyl diphosphate isomerase (designated as SlIPI) was isolated from tomato based on tentative consensus (TC183769) and unigene SGN-U569721 sequences. The SlIPI cDNA contained a 708-bp open reading frame (ORF) encoding a 235-amino-acid protein. The deduced SlIPI protein had an isoelectric point of 5.06 and molecular weight of about 27.18 kDa. Amino acid sequence comparison analysis showed 83–95% similarity to IPIs from other plant species. Phylogenetic analysis revealed that SlIPI had the closest relationship to IPI from Nicotiana tabacum. The SlIPI was likely to be localized in cytoplasm; while, SlIPI2 contained a chloroplast transit peptide. A three dimensional structure modeling revealed that the structure of SlIPI was similar to that of SlIPI2. Tissue expression analysis indicated that SlIPI was constitutively expressed, with the highest expression level detected in the root. Heterologous expression of the recombinant SlIPI in engineered Escherichia coli resulted in the production and accumulation of carotenoid in E. coli, thus confirming that the SlIPI was a functional gene.