草莓转基因研究进展

转基因是一项成熟的技术,在草莓中得到广泛应用。本文综述了农杆菌介导的草莓转基因研究进展。     

辣椒转基因植株再生

用改建的农杆菌转化辣椒,已建立有效的转化两再生系统。辣椒无菌苗（１２天苗龄）子叶在再生培养基（ＭＳ＋３ｍｇ／Ｌ ＢＡ）上预培养２天,再用农杆菌感染,共培养２天,再转入含Ｋｍ（１００μｇ／ｍｌ）的再生培养基中培养２－３周后,子叶基部有多丛芽形成。分切多丛芽,将芽转选择性的芽伸长培养基（ＭＳ基本成分＋Ｂ５维生素类＋２ｍｇ／Ｌ ＢＡ＋７５μｇ／ｍｌ）上,待芽长至２－３ｃｍ后,切下并转入生根培养基（ＭＳ＋     

草莓叶片再生芽及遗传转化系统的建立

本文从五个草莓品种中筛选了再生频率高的品种Ｍ１４,并进一步提高其再生频率至１００％,单叶盘再生芽数至１０．０个;石蜡切片法观察其芽多起源于愈伤组织,少数由叶细胞脱分化后直接形成;该再生体系用于根癌农杆菌菌株ＥＨＡ１０５介导的基因转化,并以１４．５％频率得到抗卡那霉素的抗性芽,初步鉴定是转化芽。上述结果表明频率稳定的草莓品种Ｍ１４叶片再生芽及遗传转化系统已经形成,并可以用于转基因研究。     

草莓组织培养研究初报

取草莓茎尖,进行离体培养,分化出再生植株、完正植株放于低温(5—10℃)处,壮苗锻炼、获得同步苗、移栽成活率80％以上,通过电镜检测茎尖苗无病毒粒体、无毒草莓所内小区试验获得增产13.9～22.48％的明显效果。     

基因枪转化小麦幼胚的再生培养与转基因植株的获得

以小麦幼胚为受体,用基因枪法对Trx-S反义基因 目的基因 和Bar基因 标记基因 进行了共转化,以轰击后的小麦幼胚为实验材料,对幼胚培养的基本培养基、分化和生根培养基进行了筛选优化.结果表明:4种基本培养基中,L3培养基的成愈率最高,且增殖速度快;MS培养基次之.以L3为基本培养基,分化培养基中添加NAA1mg·L-1和ZT2mg·L-1配比对愈伤组织诱导分化的效果最好,分化率达到50%以上.1/2MS培养基中添加IAA0.8mg·L-1的生根效果好,且移栽成活率高.以优化的培养方案对来自7个小麦品种的幼胚进行转化与再生培养,多数品种的出愈率都达到90%以上,分化率在40%以上,并在5个品种上获得再生植株,经检测证实在4个品种上获得转基因再生植株.     

发根农杆菌LBA9402Bin19转化红豆草及再生转基因植株

Hypocotyl segments of Onobrychis viciaefolia were transformed by Agrobacterium rhizogenes LBA9402 which harboured pBin19 and pRi1855. Seedling age and preculture time of hypocotyl segments influenced the transformation frequency. Paper electrophoresis revealed that 70% of single hairy root cultures could synthesize agropine. Calli were induced from hairy root segments on MS medium containing 0-9.05 mumol/L 2,4-D and 0-2.22 mumol/L 6-BA at first, then they were transferred onto MS0 medium without kanamycin for regeneration. Constitution and concentration of phytohormones in callus induction media affected subsequent regeneration of calluses on MS0 medium remarkably. Regeneration frequency and shoot number per callus declined when 2,4-D concentration in callus induction media increased from 4.52 to 9.05 mumol/L, while they ascended when 6-BA in callus induction media increased from 0 to 2.22 mumol/L. On MS medium supplemented with 4.52 mumol/L 2,4-D and 2.22 mumol/L 6-BA, only 14.2% hairy root segments could produce calluses, but the regeneration frequency reached 58.1% and the shoot number per callus was 37.2. In 32 analysed plants regenerated from 8 kanamycin resistant hairy root lines, 25 were nptII positive and showed different copy numbers.     

甘薯转基因研究进展

甘薯是重要的粮食、饲料和工业原料作物,同时也是新型的高能源作物。综述甘薯植株再生体系的建立及转抗除草剂、抗逆、抗病毒、抗病、抗虫、品质改良等基因方面的研究进展。此外,还对转基因甘薯的发展前景作简要展望。     

高羊茅转基因研究进展

高羊茅为很重要的多年生冷季型草坪草,生物技术在其品种改良中具有很大的应用潜力。本文对高羊茅植株再生体系的建立及遗传转化方面的研究进展进行了综述。同时,对高羊茅转基因研究中存在的问题和前景作了讨论。     

根癌农杆菌介导转录因子CBF1基因对草莓的转化

以草莓(Fragaria ananassa Duch)品种“达斯莱克特“(Darselect)为试材,用根癌农杆菌介导的方法,将转录因子CBF1基因导入草莓叶盘细胞,经多次筛选获得了转基因植株.转化植株经PCR检测,证实了CBF1基因已经整合到草莓的基因组中.以电解质渗透法检测了植株的抗寒性,结果显示转基因草莓的抗寒能力较未转化植株有明显提高,且不同转基因株系之间提高程度有着差异.     

Recent advances in rice biotechnology--towards genetically superior transgenic rice

Rice biotechnology has made rapid advances since the first transgenic rice plants were produced 15 years ago. Over the past decade, this progress has resulted in the development of high frequency, routine and reproducible genetic transformation protocols for rice. This technology has been applied to produce rice plants that withstand several abiotic stresses, as well as to gain tolerance against various pests and diseases. In addition, quality improving and increased nutritional value traits have also been introduced into rice. Most of these gains were not possible through conventional breeding technologies. Transgenic rice system has been used to understand the process of transformation itself, the integration pattern of transgene as well as to modulate gene expression. Field trials of transgenic rice, especially insect-resistant rice, have recently been performed and several other studies that are prerequisite for safe release of transgenic crops have been initiated. New molecular improvisations such as inducible expression of transgene and selectable marker-free technology will help in producing superior transgenic product. It is also a step towards alleviating public concerns relating to issues of transgenic technology and to gain regulatory approval. Knowledge gained from rice can also be applied to improve other cereals. The completion of the rice genome sequencing together with a rich collection of full-length cDNA resources has opened up a plethora of opportunities, paving the way to integrate data from the large-scale projects to solve specific biological problems.     

红颜草莓叶盘再生及遗传转化体系的优化

草莓离体组织再生和遗传转化体系的研究对草莓分子育种至关重要。为了优化农杆菌介导草莓品种红颜(Fragaria×ananassa Duch.Benihoppe)的遗传转化体系,本研究以红颜草莓组培苗的离体叶盘作为试验材料,首先确定了其离体再生的最佳条件,对影响转化效率的因素进行优化,获得了稳定高效的再生及转化体系。结果表明,红颜草莓离体叶盘最佳暗培养时间为9 d,最佳愈伤诱导培养基为MS+TDZ(2. 0 mg/L)+IBA(0. 1 mg/L)+2,4-D(0. 1 mg/L),最佳愈伤分化培养基为MS+6-BA(0. 5 mg/L)+NAA(0. 1 mg/L),转化体系的最佳组合为预培养2 d、添加300μmol/L的AS、以OD600nm=0. 6的EHA105型的农杆菌浸染5 min、共培养5 d。经优化后的红颜草莓叶盘再生及遗传转化体系对该品种的进一步优化和选育有重要意义。     

枸杞生物技术研究进展

综述了国内外枸杞生物技术研究进展,包括了枸杞无性植株的再生、胚培养在育种中的应用;单倍体和多倍体,单细胞和原生质体培养技术;体细胞突变体筛选以及遗传转化再生植株的研究进展。     

植物无融合生殖研究新进展

无融合生殖是指不经过雌雄配子融合而产生种子的一种特殊生殖方式,能使基因型的杂合性得以保持,从而可以固定杂种优势,对作物育种具有极其重要的意义。目前大量的研究都在设法将无融合生殖作为一种重要的植物育种手段。本文对近几年来无融合生殖新种质资源的发现、主要研究方法、遗传机制和相关基因等方面的最新进展作了介绍,并对无融合生殖研究中存在的问题和发展前景作了讨论。     

转基因植物中RNA介导的病毒抗性研究进展

利用病毒核酸序列培育抗病毒的转基因植物是一个重要的抗病毒基因工程策略。虽然很多种病毒的不同核酸序列已被使用并证明转基因植物有不同程度的抗病毒效果，但其抗病机制大多不清楚。目前至少有两种明显不同的抗病机制类型：一种是要求病毒编码的蛋白质的表达；另一种是仅仅依靠转基因的ＴＮＡ转录。本文综述了这种ＲＮＡ介导的抗性特点、分子生物学、抗病机制，以及与共抑制的相似性，并对ＲＮＡ介导的病毒抗性的意义加以讨论。     

Overexpression of the acidic dehydrin WCOR410 improves freezing tolerance in transgenic strawberry leaves

Progress in freezing tolerance (FT) improvement through plant breeding approaches has met with little success in the last 50 years. Engineering plants for greater FT through plant transformation is one possible way to reduce the damage caused by freezing. Here, we report an improvement of the selection procedure and the transfer of the wheat Wcor410a acidic dehydrin gene in strawberry. The encoded protein has previously been shown to be associated with the plasma membrane, and its level of accumulation has been correlated with the degree of FT in different wheat genotypes. The WCOR410 protein was expressed in transgenic strawberry at a level comparable with that in cold-acclimated wheat. Freezing tests showed that cold-acclimated transgenic strawberry leaves had a 5 degrees C improvement of FT over wild-type or transformed leaves not expressing the WCOR410 protein. However, no difference in FT was found between the different plants under non-acclimated conditions, suggesting that the WCOR410 protein needs to be activated by another factor induced during cold acclimation. These data demonstrate that the WCOR410 protein prevents membrane injury and greatly improves FT in leaves of transgenic strawberry. A better understanding of the limiting factors allowing its activation may open up the way for engineering FT in different plant organs, and may find applications for the cryopreservation of human tissues and organs.     

Recent advances in transgenic technology

Techniques that allow modification of the mammalian genome have made a considerable contribution to many areas of biological science. Despite these achievements, challenges remain in two principal areas of transgenic technology, namely gene regulation and efficient transgenic livestock production. Obtaining reliable and sophisticated expression that rivals that of endogenous genes is frequently problematic. Transgenic science has played an important part in increasing understanding of the complex processes that underlie gene regulation, and this in turn has assisted in the design of transgene constructs expressed in a tightly regulated and faithful manner. The production of transgenic livestock is an inefficient process compared to that of laboratory models, and the lack of totipotential embryonic stem (ES) cell lins in farm animal species hampers the development of this area of work. This article highlights recent progress in efficient transgene expression systems, and the current efforts being made to find alternative means of generating transgenic livestock.     

Progress in the biotechnology of trees

An increasing world population and rise in demand for tree products, especially wood, has increased the need to produce more timber through planting more forest with improved quality stock. Superior trees are likely to arise from several sources. Firstly, forest trees can be selected from wild populations and cloned using macropropagation techniques already being investigated for fruit tree rootstocks. Alternatively, propagation might be brought aboutin vitro through micropropagation or sustained somatic embryogenesis, with encapsulation of the somatic embryos to form artificial seeds. Tree quality could be improved through increased plant breeding and it is likely that experienced gained, to date, in the breeding of fruit species will be useful in devising strategies for forest trees. Since the development of techniques to regenerate woody plants from explant tissues, cells and protoplasts, it is now feasible to test the use of tissue culture methods to bring about improvements in tree quality. Success has already been achieved for tree species in the generation of somaclonal and protoclonal variation, the formation of haploids, triploids and polyploids, somatic hybrids and cybrids and the introduction of foreign DNA through transformation. This review summarizes the advances made so far in tree biotechnology, and suggests some of the directions that it might take in the future.     

Recent advances in transgenic arthropod technology

The ability to insert foreign genes into arthropod genomes has led to a diverse set of potential applications for transgenic arthropods, many of which are designed to advance public health or improve agricultural production. New techniques for expressing foreign genes in arthropods have now been successfully used in at least 18 different genera. However, advances in field biology are lagging far behind those in the laboratory, and considerable work is needed before deployment in nature can be a reality. A mechanism to drive the gene of interest though a natural population must be developed and thoroughly evaluated before any field release, but progress in this area has been limited. Likewise, serious consideration of potential risks associated with deployment in nature has been lacking. This review gives an overview of the most promising techniques for expressing foreign genes in arthropods, considers the potential risks associated with their deployment, and highlights the areas of research that are most urgently needed for the field to advance out of the laboratory and into practice.