转座子标签法及其在大豆功能基因组研究中的应用前景

转座子标签法是克隆未知基因的有效方法之一.本文介绍了转座子标签法的基本原理、步骤、方法及其在植物基因克隆中的应用情况,并对该方法在大豆突变体库构建和功能基因组研究中的应用前景进行了讨论.     

Ac/Ds转座子系统及其在玉米突变体库构建中的应用

Ac/Ds转座子系统是研究玉米功能基因组学的重要工具。Ac/Ds转座子系统以其在基因组中的低拷贝、倾向插入基因外显子、可以在同一基因不同位点造成突变等独特优势,在构建玉米突变体库和进行基因功能鉴定方面具有重要应用前景。综述了Ac/Ds转座子系统的插入特点、转座机制、在玉米突变体库构建中的应用以及我国玉米突变体库的现状,并对我国玉米Ac/Ds突变体库的研究提出展望。     

诱变育种技术在大豆育种与基因挖掘中的应用现状及展望

植物诱变育种能够创造许多优异变异资源,诱变获得的突变体可以作为种质材料,为大豆新品种培育提供丰富的资源;构建的突变体库也有助于大豆功能基因组研究的开展,可为特定性状的研究提供遗传材料。本文介绍诱变育种技术在大豆生长特性、品质和抗性改良育种中的应用,分析利用诱变突变体库进行大豆生长特性、品质性状改良和抗性相关基因挖掘的研究进展,介绍诱变技术与其他生物技术相结合发掘目的基因的应用现状,并展望今后大豆诱变育种技术在基因挖掘方面的应用前景,以期能更好地运用诱变育种技术推动大豆遗传研究和品种选育。     

玉米Mutator转座子结构特征和基因克隆的研究进展

Mutator（Mu）转座子是已发现的植物中转座活性最强的转座子,其较高的转座频率以及趋向于插入单拷贝功能基因转座的特性,使其成为构建玉米突变体库的一个主要方法。当前玉米B73品系基因组测序已经基本完成,利用反向遗传学方法,研究玉米基因的功能更为方便。文中简要介绍Mu转座子的结构特征以及Mu的分类,介绍3种克隆Mu转座子标签插入位点侧翼序列的技术,对Mu研究所存在的问题进行分析,展望Mu的应用。     

大豆突变体库构建研究进展

大豆突变体库是大豆农艺性状变异的重要来源,可以作为选育新品种资源和大豆基因功能研究的基础。综述了几种常用大豆突变体库的构建方法及其构建特点和应用范围,介绍了一些突变体库构建的新方法及其优缺点,并对这些新方法在大豆突变体库构建应用中进行了展望,为大豆育种实践和基因功能研究拓宽思路和提供参考。     

60Co-γ和EMS诱变“天隆一号”突变体库变异特征的初步分析

为培育新的适应长江流域气候类型的大豆品种,利用60Co-γ射线和EMS分别对大豆天隆一号的种子进行诱变处理,构建大豆突变体库。对350份有表型变异的株系进行连续两年田间鉴定,运用60对SSR标记进行分子检测,并对籽粒表型变化明显的突变株进行苯基丙酸类代谢主要酶qPCR分析。结果表明:350份材料中有145份在株高、叶形、花色、种皮色、结荚习性等方面有稳定可见的表型变异,101份材料中检测到与野生型天隆一号存在至少1个SSR位点差异,其中M3-SD-1与M3-SD-2有超过10个标记的差异。SSR分析表明,表型发生变异的突变体主要是由DNA变化引起的,且突变体发生了多位点变异,突变位点也彼此不同。qPCR检测结果显示,种皮色、脐色等发生突变的3个材料苯基丙酸类代谢途径中关键基因的表达量发生显著变化。研究结果既可以为大豆品种改良提供新的种质资源,也有助于大豆功能基因组的研究。     

籼稻93-11辐射诱变突变体库的创建及其筛选

人工诱变突变体库是植物种质资源创新和基因组功能分析的有力工具。本研究以具有优异农艺性状且已完成基因组测序的籼稻常规品种93-11(O.sativa ssp.indica cv.93-11)为材料,创建了一个包含3617个家系的辐射诱变突变体库。通过在M2和M3代各生育期的筛选,从该突变体库中获得308个表型稳定的突变体。这些突变体的表型可以分成15类,包括株高、分蘖数、株型、穗型、小穗结构、育性、叶色、叶型、抽穗期、苯达松抗性等,突变频率为0.03%~2.74%。使用反向遗传学策略,鉴定出了2个雄性不育突变体和2个苯达松敏感突变体中的基因突变位点。其中,2个雄性不育突变体的突变表型是由于CYP704B2分别在第3和第4外显子发生碱基替换和片段缺失造成的,而2个苯达松敏感突变体的突变表型是由于CYP81A6中第1和第2外显子分别缺失了一个7bp和一个23bp的片段造成的。4个突变体家系中野生型和突变体植株的分离比均符合3∶1,属单基因隐性突变。这一籼稻突变体库将有助于籼稻基因组的功能分析,并且为水稻遗传改良提供了有价值的材料。     

不同加工工艺对大豆转基因成分及调控元件的影响

以转基因大豆为试验材料,运用定性PCR的方法研究了粉碎、湿热和膨化3种加工工艺对转基因大豆内源基因Lectin、外源基因Cp4 epsps以及启动子和终止子的影响.结果表明:大豆经过100℃湿热处理15 min后,内源基因降解到407 bp以下;经过100℃湿热处理15 min后,外源基因降解到408 bp以下;在10...     

农杆菌介导大豆遗传转化影响因素研究进展

大豆基因工程育种和功能基因组分析亟需建立高效大豆转化体系。本文综述了近年来影响农杆菌介导大豆遗传转化体系的农杆菌因素、植物因素及培养条件等方面的进展,主要包括农杆菌菌株、菌株生长状态、大豆基因型、外植体类型、防御酶、内源激素及侵染和共培养方法等,为提高大豆遗传转化效率及基因工程育种等相关研究提供参考。     

大豆EMS突变体库构建及其M_1代重要农艺性状评价

构建突变体库是进行遗传学与分子生物学研究的重要前提条件之一。当前大豆突变体数量的不足,严重制约了大豆功能基因组学研究的深入开展。以南方大面积推广的大豆品种-南豆12为材料,通过EMS诱变构建了大豆EMS突变体库。统计发现,M1种子田间出苗率为34.85%,表明EMS强烈抑制大豆种子的萌发和出苗。对随机选取的913株M1植株进行了株高、单株荚数等重要农艺性状的调查。结果表明:经EMS处理后,M1植株在株高、单株荚数、节间数等方面与对照存在显著差异、表型变异丰富,其中18.07%发生矮化,11.06%表现出多荚,另有3株不育株;群体间的节间个数极差达到18。这些数据表明已成功构建了大豆EMS突变体库。在进一步的研究中,将对单个突变体进行分离、分类,并克隆相应的重要功能基因,为深入研究大豆功能基因组学以及筛选适合玉米-大豆带状复合种植模式的高光效、抗倒伏大豆品种奠定基础。     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.