根癌农杆菌介导马齿苋遗传转化体系的研究

利用马齿苋的叶片诱导出愈伤组织,再以愈伤组织为受体建立了根癌农杆菌介导的遗传转化体系。利用该转化体系得到抗性愈伤组织后,对其进行GUS组织化学染色和PCR扩增鉴定,证实为转化子,表明根癌农杆菌介导外源基因转化马齿苋的愈伤组织是完全可行的,为以后通过基因工程手段进行马齿苋的改良奠定了基础。     

农杆菌介导FT基因转化嘎拉苹果的研究

用农杆菌介导法对苹果品种嘎拉转化FT基因进行了研究,建立了苹果离体叶片高效再生体系,在含BA 5mg／L＋IAA 0．5mg／L的MS培养基上,以离体叶片远轴面（叶背面）向上,经过14d的暗培养获得再生不定芽和再生植株,再生率达97％。在转基因再生体系中,以头孢噻肟钠500mg／L和卡那霉素5mg／L,作为脱菌培养和选择培养的条件,经过感染携带拟南芥FT基因的农杆菌,获得了一批转FT基因的植株,经PCR检测,目的基因已经整合到苹果基因组中。     

苹果转基因研究进展

近年来,苹果遗传转化研究取得了较大的进展,已有多种标记基因和目的基因成功转入苹果中并且得到稳定表达和遗传。农杆菌介导法是苹果上应用的主要转化方法,叶片再生不定芽途径是被广泛应用的受体系统。影响农杆菌介导成功与否的因素很多,文章从转化方法、叶片再生能力、菌株类型以及农杆菌侵染条件等方面综述了目前有关研究成果,指出目前依然存在转化效率不高、外源基因表达强度不够、对转化植株的选择不够重视等诸多问题。     

Chromosome and plasmid-encoded N-acyl homoserine lactones produced by Agrobacterium vitis wildtype and mutants that differ in their interactions with grape and tobacco

Agrobacterium vitis causes crown gall disease on grapevines. It also induces a specific necrosis on grape roots and a hypersensitive response (HR) on tobacco that are regulated by a complex quorum-sensing regulatory system. Strain F2/5 produces at least six N-acyl-homoserine lactones (AHLs) that function as signal molecules in quorum-sensing. The AHLs differ in acyl side chain length (8–16 carbons) as determined by gas chromatography/mass spectrometry and electrospray ionization tandem mass spectrometry. Mutant derivatives of F2/5 differ in ability to cause necrosis and the HR and show variable AHL profiles as determined by a thin-layer chromatography/biosensor assay. All wildtype A. vitis strains revealed the presence of long-chain AHLs regardless of tumorigenicity or ability to cause the HR. Whereas genes encoding long-chain AHLs are predicted to reside on the F2/5 chromosome, the determinants for short-chain AHLs were shown to be located on conjugal plasmids.     

农杆菌介导的半夏GUS基因瞬时表达

采用根癌农杆菌感染半夏无菌叶片、叶柄和愈伤组织,对GUS基因的瞬间表达进行研究,并分析了不同转化受体、感染时间、菌液浓度、共培养、预培养时间、菌种对GUS基因的瞬间表达的影响。结果显示,以半夏的无菌苗叶柄和愈伤组织,在OD值为0.2的EHA101或EHA105农杆菌液中感染15 min,叶柄暗处共培养3 d,愈伤组织2 d,能够得到较高的GUS基因瞬间表达。     

Evidence of Migration and Endophytic Presence of Agrobacterium tumefaciens in Rose Plants

Agrobacterium tumefaciens was isolated from stem tumors of several rose cultivars showing that the bacterium is the causal agent of aerial galls in rose plants. No differences were observed in the characteristics of the Agrobacterium isolates from crown or aerial galls. Stem inoculation of ten rose cultivars showed that all of them were susceptible to A. tumefaciens but differences in the size of the resulting tumors were observed. The movement of A. tumefaciens in rose plants was demonstrated using two wild type strains and two antibiotic resistant mutants. Three months after inoculation, the inoculated strains were recovered in the roots, crown and below and above the inoculation site but low numbers of pathogenic Agrobacterium cells were isolated. New tumors appeared in 5% of the noninoculated wounds. A. tumefaciens was isolated from the stem at different distances from the tumor in naturally infected plants. In symptomless commercial plants, the isolation from the roots, crown and at different stem levels demonstrated the existence of systemic and latent infections in rose. Direct isolation using a nonselective and selective media with or without a previous enrichment step were efficient methods for isolating tumorigenic Agrobacterium from the different parts of rose plants.     

一种发根农杆菌介导的花生遗传转化新方法

花生是中国重要的油料作物、经济作物和豆科作物。作为世界第一花生生产国和出口国,利用遗传转化方法,加快花生生物性状和遗传育种的研究势在必行。花生根系和根瘤系统的研究对于提高花生抗性进而提高花生的产量和品质以及生物固氮能力具有重要的意义。然而,目前花生遗传转化体系还不成熟,给花生研究造成了严重的障碍。本文建立了利用发根农杆菌介导花生下胚轴形成转基因毛根和根瘤的新方法,并分别用GFP和GUS两种检测方法对该转化体系进行了检测,表明该方法是一个操作简易、高效的遗传转化方法,为利用基因工程技术对花生进行研究和遗传改良提供了一套新方法。     

瓜类蔬菜组织培养与遗传转化研究进展

概述了瓜类蔬菜组织培养过程中的主要影响因素—基因型、外植体类型,部位与生理状态、培养基、生长调节物质、碳源及其他添加物质对植株再生的影响,以及根癌农杆菌介导的瓜类蔬菜遗传转化的影响因素与研究进展。     

The Prospects of Tissue Culture and Genetic Engineering for Strawberry Improvement

Abstract

Strawberry shoot meristem cultures have been used for producing virus-free strawberry plants. Plantlet regneration from leaf mesophyll protoplasts, and Agrobacterium tumefaciens mediated genetic transformation, mark the beginning of strawberry improvement with biotechnologies. The use of biotechnological tools has a greater potential in producing strawberry plants with traits such as early maturation, frost and disease resistance, mite and nematode resistance, high yield, better quality, suitability for mechanical harvesting, shipping ability, ellgaic acid content, aroma compounds and cost-effective micropropagation. Gene identification and mapping with RFLPs or RAPDs would be desirable. Transgenic strawberries should be tested for their quality before releasing to the consumers.