大豆遗传转化研究进展

近年来大豆的遗传转化取得了较大的进展.文章结合作者实验室的工作介绍了几种主要的大豆遗传转化系统及其操作方法,并探讨了影响农杆菌介导大豆遗传转化的因素.     

基因枪在植物遗传转化中的应用

基因枪技术是近年发展起来的一项新的植物遗传转化技术,本文较为系统地介绍了基因枪的类型,以及它们各自的特点和工作原理,并对基因枪在植物遗传转化中的广泛用途作了重点介绍,文中引用用参考文献七十余篇,为进一步深入了解学科的最新研究进展提供了方便。     

植物基因转化技术在苹果遗传改良中的应用

近年来,苹果基因转化技术研究取得了较大进展,本文从转化体系,选择标记,报告基因及目的基因的遗传学行为等方面综述了苹果遗传转化研究发展现状,着重论述了其在苹果遗传改良中的应用,并对植物基因转化技术在莱果上的应用前景和应注意的几个问题进行了讨论。     

大豆转化技术

介绍近年来在大豆转基因研究中再生受体系统和转化方法等方面的研究进展。     

玉米的遗传转化

介绍近年来玉米遗传转化在受体系统、基因导入、选择标记和表达系统等方面的研究进展。     

基因枪转化技术及其在禾谷类作物遗传转化中的应用

基因枪转化法广泛用于禾谷类作物的遗传转化研究,是目前禾谷类作物遗传转化的有效方法。简要介绍了基困枪转化法的产生与发展、转化的特点以及影响转化频率的主要因素;系统地概述了基因枪法在禾谷类作物遗传转化的应用。     

纳米基因载体在植物遗传转化中的应用

纳米基因载体已成功地应用于生物医学领域并显示了优越的转染效率、良好的生物相容性和有效的基因保护作用。近年来,纳米颗粒作为基因载体在植物转导中的应用潜力越来越受到关注,也为植物遗传工程提供了新的可能性。在阐述纳米载体的特性、在植物细胞中的转导机制及转导优势的基础上,重点讨论了纳米载体在植物转基因中的应用,并对其前景进行了展望。     

基因枪在水稻遗传转化中的应用及其转化技术的优化

1983年Zambryski等人用根瘤农杆菌介导法进行烟草基因转移,获得了世界上首例转基因植株.随后,应用DNA直接导入技术如电击法(electroporation)和PEG介导法(PEG—mediated)成功地获得了转基因水稻植株.近年来,随着基因枪技术的建立和发展,水稻遗传转化成功的报道逐年增多.目前基因枪技术在植物遗传转化中的应用超过了根瘤农杆菌介导和其它转化方法的应用.这是因为基因枪转化技术不受植物种类的限制,不需要以原生质体作为转化的受体,可以将外源基因直接导入细胞、组织或器官,因而克服了根瘤农杆菌     

优化子叶节转化法培育大豆MtDREB2A转基因植株

将正交因素试验与GUS基因组织化学染色等技术相结合, 优化大豆(Glycine max)品种东农50遗传转化体系, 导入抗旱关键基因MtDREB2A。结果表明, 大豆种子表面消毒, NaClO溶液法与Cl₂气熏蒸法的去污染率分别达到98.67%和93.33%。子叶节法转GUS基因组织化学染色率(68.33%)显著高于下胚轴法(14.00%)和胚尖法(0.67%) (P<0.05)。种子萌发5天, 农杆菌(Agrobacterium tumefaciens)培养温度25°C, OD₆₀₀=0.9, 共培养5天的转GUS基因子叶节最高达72.00%; 恢复培养5天, 草丁膦(3 mg·L^-1)、头孢噻肟钠(200 mg·L^-1)和羧苄青霉素(300 mg·L^-1)筛选诱导分化的转GUS基因不定芽最多为3.33%; 优化的大豆遗传转化体系转化效率为1.11%。转MtDREB2A基因大豆东农50植株根系更加密集, 主根长度和侧根数量均显著高于对照(P<0.05), 证实MtDREB2A基因具有促进大豆根系生长的作用, 为利用该基因进行大豆抗旱育种奠定了坚实的基础并提供了理论依据。     

根癌农杆菌介导的大豆遗传转化

农杆菌介导法是大豆遗传转化的重要方法之一 ,许多实验室应用该方法得到了转基因大豆 ,但目前使用该方法进行转化的效率还比较低 ,尚需深入研究。农杆菌菌株、大豆基因型、组织培养条件、T-DNA的转移效率和转化后的筛选模式都会影响大豆转化的效率。概述了近年来根癌农杆菌介导的大豆遗传转化的一些重要成果 ,以及转化过程中大豆的易感性与农杆菌的转化能力、乙酰丁香酮促进vir基因活化、转化的受体系统和巯基混合物减轻受体材料的褐化、提高T DNA的转移效率等几个重要因素的研究进展 ,并介绍了转化中常用的几个筛选标记基因 (nptⅡ、hpt、bar基因和突变的ahas基因 )及通过共转化法去除标记基因的方法 ,同时对今后研究的重点进行了讨论.     

Regeneration of Transgenic Soybean (Glycine max) Plants from Electroporated Protoplasts

Transgenic soybean (Glycine max [L.] Merr.) plants were regenerated from calli derived from protoplasts electroporated with plasmid DNA-carrying genes for a selectable marker, neomycin phosphotransferase (NPTII), under the control of the cauliflower mosaic virus 35-Svedberg unit promoter, linked with a nonselectable mannityl opine synthesis marker. Following electroporation and culture, the protoplast-derived colonies were subjected to kanamycin selection (50 micrograms per milliliter) beginning on day 15 for 6 weeks. Approximately, 370 to 460 resistant colonies were recovered from 1 × 10⁶ electroporated protoplasts, giving an absolute transformation frequency of 3.7 to 4.6 × 10⁻⁴. More than 80% of the kanamycin-resistant colonies showed NPTII activity, and about 90% of these also synthesized opines. This indicates that the linked marker genes were co-introduced and co-expressed at a very high frequency. Plants were regenerated from the transformed cell lines. Southern blot analysis of the transformed callus and leaf DNA demonstrated the integration of both genes. Single-plant assays performed with different plant parts showed that both shoot and root tissues express NPTII activity and accumulate opines. Experiments with NPTII and mannityl opine synthesis marker genes on separate plasmids resulted in a co-expression rate of 66%. These results indicate that electroporation can be used to introduce both linked and unlinked genes into the soybean to produce transformed plants.     

Developmental Aspects of Soybean (Glycine max) Somatic Embryogenesis

A detailed study of the developmental aspects for soybean somaticembryogenesis was undertaken with emphasis on biochemical andhistological markers. The various stages of somatic embryo developmentin callus cultures have been identified and characterized. Germinatingembryos could be converted to fertile plants at a high frequency(90%). Dicamba (3, 6-dichloro-o-anisic acid) was found to bethe auxin of choice for the clear distinction of the variousdevelopmental phases of soybean somatic embryos. Differencesin their protein patterns were determined using polyacrylamidegel electrophoresis. This analysis revealed distinguishabledifferences in protein profiles amongst the various developmentalstages, especially in heart stage embryos. Histological studieson somatic embryos revealed specific tissue types which closelyresemble those reported for zygotic embryos. Further evidenceis provided that there is a close similarity in tissue differentiation,between somatic and zygotic embryogenesis although there aresome unique features in the development of somatic embryos. Glycine max, callus cultures, developmental stage, liquid cultures, neomorphs, plant regeneration, stage specific proteins, histology     

Role of Phytohormones in Soybean (Glycine max) Seed Development

Russian Journal of Plant Physiology - Phytohormones play a key important role in the sink development of the seed. Endogenous content of IAA, PAA, GA, ABA, and kinetin were estimated in two...     

Malonyl Isoflavone Glycosides in Soybean Seeds (Glycine max Merrill)

The isoflavone constituents in soybean seeds were investigated, and 9 kinds of isoflavone glycosides were isolated from the hypocotyls of soybean seeds. Three kinds were proved to be malonylated soybean isoflavones named 6″-O-malonyldaidzin, 6″-O-malonylglycitin and 6″-O-malonylgenistin by UV, MS, IR and NMR. The malonylated isoflavone glycosides as major isoflavone constituents in soybean seed were thermally unstable, and were converted into their corresponding isoflavone glycosides. All of the isoflavone components produced intensely undesirable taste effects such as bitter, astringent and dry mouth feeling.     

Translocation of Sulfate in Soybean (Glycine max L. Merr)

Sulfate translocation in soybean (Glycine max L. Merr) was investigated. More than 90% of the sulfate entering the shoot system was recoverable in one or two developing trifoliate leaves. In young plants, the first trifoliate leaf contained between 10 to 20 times as much sulfate as the primary leaves, even though both types of leaf had similar rates of transpiration and photosynthesis. We conclude that most of the sulfate entering mature leaves is rapidly loaded into the phloem and translocated to sinks elsewhere in the plant. This loading was inhibited by carbonylcyanide m-chlorophenylhydrazone and selenate. At sulfate concentrations below 0.1 millimolar, more than 95% of the sulfate entering primary leaves was exported. At higher concentrations the rate of export increased but so did the amount of sulfate remaining in the leaves. Removal of the first trifoliate leaf increased two-fold the transport of sulfate to the apex, indicating that these are competing sinks for sulfate translocated from the primary leaves. The small amount of sulfate transported into the mesophyll cells of primary leaves is a result of feedback regulation by the intracellular sulfate pool, not a consequence of their metabolic inactivity. For example, treatment of plants with 2 millimolar aminotriazole caused a 700 nanomoles per gram fresh weight increase in the glutathione content of primary leaves, but had no effect on sulfate aquisition.     

大豆籽粒大小的发育遗传分析

籽粒大小是大豆产量的一个重要因素。有关大豆籽粒的遗传学和生理生态学研究已有一些研究,而对于籽粒发育过程中的遗传效应却报道很少。文章采用种子广义遗传模型,分析了大豆双列杂交组合3个世代遗传材料8个时期的鲜籽粒大小和干籽粒大小的数据,应用非条件和条件遗传方差及相关方法分析了发育遗传规律。8个时期的亲本、F1、F2的鲜籽粒大小和干籽粒大小的平均数分别在9／6和9／13达到最高值,鲜籽粒大小在9／6后迅速下降,干籽粒大小在9／13后区于稳定。非条件方差分析表明在整个生育期中,胚遗传效应、细胞质遗传效应和母体植株遗传效应对大豆鲜籽粒大小和干籽粒大小有影响。在多数生育阶段中,细胞质和母体植株的遗传效应对鲜籽粒大小和干籽粒大小影响较大。条件方差分析表明,在大豆生育期中,各遗传体系的基因间断性表达。在多数生育阶段中,细胞质和母体植株的净遗传效应高于胚净遗传效应。不同时期的各遗传体系的基因效应可以单独或同时影响鲜籽粒大小和干籽粒大小的最终表现。8／16的胚加性效应、8／9和8／16的胚显性效应、8／2和8／16的母体植株显性效应影响到鲜籽粒大小的最终表现。8／2和9／13的胚加性效应、8／9的细胞质效应、8／2的母体植株显性效应对干籽粒大小的最终表现有影响。     

大豆转基因体系的研究进展

从大豆的转基因方法和受体系统两个方面概述大豆转基因体系的最新研究进展,并讨论了大豆遗传转化的主要障碍及可能的解决途径。作者认为,以根癌农杆菌介导大豆子叶节和基因枪轰击大豆未成熟子叶是较有效的大豆遗传化系统。目前,在大豆遗传转化研究中存在着大豆组织培养体系有待于进一步完善、遗传转化率较低、重复性差、大豆受体基因型单一等问题,建立新的、高效和稳定的大豆组织培养体系,提高生产上栽培大豆品种的组织培养能力,改遗传转化现有的单一基因为多基因,可能是解决上述问题的有效途径。     

大豆转基因的研究进展

大豆转基因操作中常用的再生受体系统有：器官发生受体系统,体细胞胚胎发生受体系统,原生质体受体系统,以及所使用的转基因方法： 直菌介导法,基因枪法,PEG法等,并对今后大豆转基因存在的一些技术问题进行了探讨。     

Early Development of the Seed Coat of Soybean (Glycine max)

Although the development of the soybean ovule has been fairlywell studied, knowledge of the sequence of events in the seedcoat during the first 3 weeks after flowering is incomplete.The goal of the present study was to document, using light microscopy,the early development of the soybean seed coat with respectto changes in structure and histochemistry. At anthesis, theseed coat consists of an outer layer of cuboidal epidermal cellssurrounding several layers of undifferentiated parenchyma (whichtogether constitute the outer integument), and an inner layerof cuboidal endothelial cells (the inner integument). At 3 dpost anthesis (dpa), the inner integument has expanded to includethree to five layers of relatively large cells with thick, heavily-stainingcell walls immediately adjacent to the endothelium. By 18 dpa,the outer integument has developed into a complex of tissuescomprised of an inner layer of thick-walled parenchyma, an outerlayer of thin-walled parenchyma containing vascular tissue whichhas grown down from the lateral vascular bundles in the hilumregion, a hypodermis of hourglass cells, and palisade layer(epidermis). The thick-walled parenchyma of the inner integumenthas become completely stretched and compressed, leaving a single,deeply staining wall layer directly above the endothelium. At21 dpa, the outermost cells of the endosperm have begun to compressthe endothelium. At 45 dpa (physiological maturity) the seedcoat retains only the palisade layer, hourglass cells, and afew layers of thin-walled parenchyma. The innermost layer ofthe endosperm, the aleurone layer, adheres to the inside ofthe seed coat. This knowledge will be invaluable in future studiesof manipulation of gene expression in the seed coat to modifyseed or seed coat characteristics. Copyright 1999 Annals ofBotany Company Soybean, Glycine max, seed coat, development, aleurone.