农杆菌介导马铃薯转化体系的优化及转基因马铃薯的耐盐性研究

通过农杆菌介导的方式将獐茅液泡膜Na~+/H~+逆向转运蛋白基因(AlNHX)表达在马铃薯中,并对影响马铃薯转化的几种因素(抗生素浓度、农杆菌菌液浓度、共培养时间等)进行优化。结果表明:最适农杆菌菌液浓度是OD600=0.6,最适侵染时间是5min,最适共培养时间是2d,马铃薯转化中最适头孢霉素浓度是400mg/L;经PCR检测确认的转基因马铃薯植株在含0.7%NaCl的培养基中可以生长,而野生型马铃薯无法在此培养基中正常生长。在盐胁迫条件下,转基因马铃薯的Na~+、K~+含量及K~+/Na~+的比值均高于野生型马铃薯。研究证实马铃薯植物的的耐盐性可以通过农杆菌转化导入獐茅液泡膜Na~+/H~+逆向转运蛋白基因而得到提高。     

Development and identification of glyphosate-tolerant transgenic soybean via direct selection with glyphosate

Glyphosate-tolerant soybean is the most widely planted genetically modified crop worldwide. However, soybean remains recalcitrant to routine transformation because of the low infection efficiency of Agrobacterium to soybean and lack of useful selectable markers. In this study, several Agrobacterium strains and cell densities were compared by transient expression of the GUS gene. The results showed that Agrobacterium strain Ag10 at cell densities of OD_(600) of 0.6–0.9 yielded the highest infection efficiency in Agrobacterium-mediated soybean cotyledonary node transformation system. Meanwhile, a simple and rapid method was developed for identification of glyphosate tolerance in putative T_0 transgenic plants, consisting of spotting plantlets with 1 μL Roundup~?. The whole cycle of genetic transformation could be shortened to about 3 mon by highly efficient selection with glyphosate during the transformation process and application of the spot assay in putative T_0 transgenic plantlets. The transformation frequency ranged from 2.9 to 5.6%. This study provides an improved protocol for development and identification of glyphosate-tolerant transgenic soybeans.     

产肠毒素大肠杆菌K88ac-STⅡ-LTA2/LTB融合基因在苜蓿中的表达

为提高农杆菌介导的苜蓿遗传转化效率,获得转K88ac-STⅡ-LTA2/LTB基因苜蓿植株,以苜蓿下胚轴为外植体,对影响遗传转化的预培养时间、农杆菌菌液浓度、筛选方式等进行研究.结果表明,苜蓿下胚轴预培养3 d,菌液浓度为OD6000.5,筛选剂Kan浓度第一阶段和第二阶段分别为30和50 mg/L ,延迟筛选7 d时转化效率最高.对转基因苜蓿进行PCR和PT-PCR检测,初步证实目的基因已经整合到苜蓿基因组中,转化率达28.4%.     

影响复合针介导的大豆子叶节遗传转化的主要因素的研究

以萌动1d的半片大豆种子为试验材料,用复合针针刺2次,农杆菌LBA4404/pCAMBIA1201侵染,共培养3d,GUS染色检测瞬时表达效率。结果表明:不同基因型和乙酰丁香酮(As)浓度对转化效率有显著影响,As浓度为100或200μmol/L时,转化效率显著提高,其中以合丰25的转化效率最高,平均为8.6个蓝色斑点;农杆菌的侵染时间以30 min为宜;农杆菌的侵染浓度以OD600为0.6时最佳,平均为9.8个蓝色斑点。     

Optimization of Agrobacterium tumefaciens-Mediated Immature Embryo Transformation System and Transformation of Glyphosate-Resistant Gene 2mG2-EPSPS in Maize (Zea mays L.)

Since maize is one of the most important cereal crops in the world, establishment of an efficient genetic transformation system is critical for its improvement. In the current study, several elite corn lines were tested for suitability of Agrobacterium tumefaciens-mediated transformation by using immature embryos as explants. Infection ability and efficiency of transformation of A. tumefaciens sp. strains EHA105 and LBA4404, different heat treatment times of immature embryos before infection, influence of L-cysteine addition in co-cultivation medium after transformation, and how different ways of selection and cultivation influence the efficiency of transformation were compared. Glyphosate-resistant gene 2mG2-EPSPS was transformed into several typical maize genotypes including 78599, Zong 31 and BA, under the optimum conditions. Results showed that the hypervirulent Agrobacterium tumefaciens sp. strain EHA105 was more infectious than LBA4404. Inclusion of L-cysteine (100 mg L^?1) in co-cultivation medium, and heating of the immature embryos for 3 min prior to infection led to a significant increase in the transformation efficiency. Growth in resting medium for 4-10 d and delaying selection was beneficial to the survival of resistant calli. During induction of germination, adding a high concentration of 6-BA (5 mg L^?1) and a low concentration of 2,4-D (0.2 mg L^?1) to regeneration medium significantly enhanced germination percentage. Using the optimized transformation procedure, more than 800 transgenic plants were obtained from 78599, Zong 31 and BA. By spraying herbicide glyphosate on leaves of transgenic lines, we identified 66 primary glyphosate-resistant plants. The transformation efficiency was 8.2%. PCR and Southern-blot analyses confirmed the integration of the transgenes in the maize genome.     

农杆菌介导的烟草瞬时表达影响因素研究

通过探究根癌农杆菌(Agrobacterium tumefaciens)介导的烟草瞬时表达体系的影响因素,确定烟草瞬时表达的最佳条件,为目的基因的功能研究提供技术支持。利用马铃薯晚疫病抗性基因RB和致病疫霉菌效应基因Avrblb 1作为报告基因,采用农杆菌介导的注射渗透法,摸索农杆菌菌悬液OD600值和菌系(遗传背景)、烟草品种及其生长时期等因素,确定烟草高效的基因瞬时表达条件。研究结果表明:介导烟草基因瞬时表达的根癌农杆菌菌悬液适宜OD600值为0.3~0.8;在菌悬液OD600值为0.1及以上时,AGL1、GV3101和C58C1介导的报告基因瞬时表达效率相似,均引发较强的叶片坏死反应;在农杆菌菌悬液OD600值小于0.1时,AGL1介导的瞬时表达效率最高。测试的烟草品种都具备较高的瞬时表达效率,苗龄6~8周的烟草适合分析。通过测试农杆菌菌悬液OD600值和菌系(遗传背景)、烟草品种及其生长时期等因素,确定本氏烟和普通烟均可实现基因高效瞬时表达的条件。     

农杆菌介导茄子叶转基因体系的建立

本文选择3份茄核心种质,研究Hyg B浓度、农杆菌浓度(OD600)、侵染时间、共培养时间对茄遗传转化效果的影响。同时,选择7份核心种质进行转化研究,以确定茄遗传转化的最佳受体。结果表明,筛选阳性植株的最适Hyg B浓度为50mg/L;菌液浓度(OD_(600))0.6,侵染外植体15min和共培养4d时,抗性愈伤百分率最高;获得的Hyg B抗性植株,经PCR检测及GUS组织化学鉴定,确认外源基因GUS已成功整合到茄基因组中;不同茄遗传型转化效果差异较大,最高转化率可达到10%。     

Strawberry FaEtr2 gene RNAi expression vector construction and genetic transformation

The short hairpin RNA (shRNA) expression vector of the FaEtr2 gene was constructed by inserting the sense fragment into the constructed antisense vector of FaEtr2 (pBI121-Anti-Etr2) in sense orientation. The constructed RNA interference (RNAi) expression vector was transformed into Agrobacterium fumefeciens LBA4404 and used to infect strawberry leaves. Using in vitro plantlet leaves as explants, the transformation conditions of All-Star strawberry were studied systemically. The results showed that infecting the leaves with A. fumefeciens resuspension liquid of OD₆₀₀ = 1.0 by pre-culturing for 3 d, co-culturing for 3 d, infecting for 10 min, and adding acetosyringone (AS) 50–100 μmol·L⁻¹ was suitable for genetic transformation of All-Star strawberry. Seven lines of transgenic plants were preliminarily identified by PCR and β-glucurondiase (GUS) histochemical staining.     

百合遗传转化体系的建立

通过根癌农杆菌介导的遗传转化方法,建立了百合金黄精灵(ButterPixie)鳞茎的遗传转化体系。确定了适宜百合转化的筛选剂草甘磷的浓度:芽分化阶段为1.6mg.L-1,根分化阶段为0.8mg.L-1。除菌剂头孢的使用浓度为500mg.L-1。并且确定OD600=0.5的菌液浓度侵染20min,共培养pH5.2培养3d时对百合有最高转化效率。研究确定了预培养时间为4d,在共培养培养基中去除NH4NO3或加入阿魏酸均可提高转化效率。得到抗性植株12株,PCR初步检测发现其中7株为PCR阳性植株,转化效率为58.3%。     

优化农杆菌介导的月季遗传转化系统的研究

为了建立月季品种‘萨蔓莎’根癌农杆菌介导的遗传转化系统，我们通过衡量GUS基因瞬间表达水平，探讨了各因子对基因转化的影响.结果表明:外植体、光照条件、共培养培养基中无机盐含量及乙酰丁香酮（AS）含量是重要的影响因子；共培养时间、共培养温度及农杆菌菌液浓度对根癌农杆菌的生长以至基因转化有重要影响.优化后的转化条件为:将月季胚性愈伤组织与OD６００值为0.5～0.8的农杆菌菌液侵染20min，然后在含300μmol/L AS并且无机盐减半的MS培养基上黑暗、23℃条件下共培养3d.      

利用农杆菌浸种法建立白三叶草遗传转化体系的研究

以白三叶萌动种子作为转化受体,利用npt-Ⅱ筛选基因对影响农杆菌介导的遗传转化外部因素进行深入     

响应面优化大肠杆菌生物膜的培养条件

利用响应面法对大肠杆菌生物膜的培养条件进行优化。在单因素试验基础上,以细菌浓度、pH和培养时间为自变量,生物膜形成量为响应值,根据中心组合(Box-Benhnken)试验设计原理,研究各自变量及其交互作用对生物膜形成的影响,依据回归分析确定各培养条件的最优值,并通过激光共聚焦显微镜观察大肠杆菌生物膜的形成。结果表明,大肠杆菌生物膜的最佳培养条件为:LB培养基pH7.5,细菌接种量为1.2×10~7 cfu/mL,培养时间11.5 h。在该优化条件下,大肠杆菌生物膜的形成量OD_(600nm)可达0.60左右;通过激光共聚焦显微镜观察可见,此时形成大量的细菌聚集体,80%的视野已经被细菌覆盖,细菌活性很高,生物膜形成量达到高峰。     

Preparation of dry flowable formulations of Clonostachys rosea by spray drying and application for Sclerotinia sclerotiorum control

A dry flowable formulation of Clonostachys rosea with fungicidal activity against Sclerotinia sclerotiorum was prepared by spray drying. The formulation was optimized by a four-factor, three-level orthogonal experiment to screen inert ingredients and spray-drying conditions. The optimal dry flowable formulation of C. rosea included 30% C. rosea (ratio of conidia powder and its fermentation broth is 1:3), 3% Morwet EFW, 4% K12, 10% Morwet D425, 9% sodium salt of polynaphthalene sulphonic acid (NNO), 5% croscarmellose sodium, 5% (NH₄)₂SO₄, 0.5% carboxymethyl cellulose sodium (CMC-Na), 1% oxalic acid and palygorskite (carrier) up to 100%. The formulation exhibited good physical characteristics, such as high dispersibility, viability and a long shelf life. Plate antagonism tests and pot trials indicated that the dry flowable formulation was very effective against S. sclerotiorum, with control efficiency of up to 88.30%. This dry flowable formulation of C. rosea is a new potential commercial fungicide for spray drying to control S. sclerotiorum.     

农杆菌介导法将LFY基因导入苹果的研究

以M26苹果叶片为外植体,利用GUS瞬时表达率,对农杆菌介导法转化苹果的因素进行优化,通过含LFY基因的根癌农杆菌EHA105转化苹果叶片,获得了提早开花的转基因植株。结果表明:以OD600=0.3~0.5农杆菌菌液侵染叶片,25℃条件下共培养,共培养后的叶片延迟筛选3 d,在附加卡那霉素30 mg/L的再生培养基中选择培养,转化芽再生率可达6.97%。PCR检测初步证明目的LFY基因已整合到苹果基因组中。     

利用农杆菌介导法获得转ipt基因半夏植株

以贵州珍珠半夏Pinellia ternate(Thunb.)Breit为材料,采用根癌农杆菌介导法,探索了影响半夏遗传转化效率的主要因子.结果表明,卡那霉素的最佳筛选浓度是100 mg/L,侵染时间、共培养时间、乙酰丁香酮浓度对转化频率都有一定的影响.其中侵染时间为20 min,共培养时间为3 d,乙酰丁香酮的浓度控制在60～100 mg/L时可以有效提高遗传转化效率.在此基础上辅以超声波处理5 min,可以有效提高叶柄转化的瞬时表达率.对抗性转化植株进行Gus染色和PCR检测,结果表明外源基因ipt已经整合到半夏基因组中.     

Effects of different concentrations of super-absorbent polymers on soil structure and hydro-physical properties following continuous wetting and drying cycles

Super-absorbent polymers (SAPs) are widely used chemical water-saving materials, which play an active role in the accumulation of soil water and the improvement of soil structure. Little is known about their performance with repeated usage or about factors influencing their efficiency under alternate wetting and drying cycles. In this study, various concentrations of SAP (0, 0.1, 0.2 and 0.3%) in soil following three continuous wetting and drying cycles (T1, T2 and T3), were studied to determine effects on soil structure stability and hydro-physical properties. The results indicated that the SAP improved soil water supply capacity under conditions of mild drought (T2) and sufficient irrigation (T3) at concentrations of 0.2 and 0.3%, but a reduction was observed under severe drought conditions (T1), which was negatively correlated with the SAP concentration. The physical adsorption of the SAP by soil and the chemical connection between the SAP and soil mineral colloids as Si-O-Si bonds, -OH bonds and different crystalline silica were the important factors that directly lead to the reduction of water retention capacities of the SAP with alternating wet and dry conditions. Compared with the control, the soil liquid phase ratios of the SAP treatments were increased by 8.8–202.7% in the T1 and T2 cycles, which would have led to a decrease in the soil air phase ratios. After repeated wetting and drying cycles, the SAP treatments increased the amount of >0.25 mm soil aggregates and the contents of water-stable macro-aggregate (R_0.25), and decreased the amount of <0.053 mm soil aggregates, especially with higher concentrations of the SAP. Increases in mean weight diameter (MWD) and geometric mean diameter (GMD), and declines in fractal dimension (D) and unstable aggregates index (E_LT) were all observed with the SAP treatments, which indicated an improvement in soil stability and structure. It was concluded that the distribution and stability of soil aggregates and soil water supply capacity was closely related to SAP concentration, soil moisture condition and the interaction between the SAP and soil particles.     

根癌农杆菌介导转录因子CBF1基因对菊花的转化

利用根癌农杆菌介导法对菊花品种'小金黄'叶片进行遗传转化,研究影响菊花转化的若干因素,建立一套高效的遗传转化体系.结果表明:2 d的预培养,OD600值约为0.5的农杆菌菌液添加50 mg/L AS,侵染时间3 min,2 d的共培养,从分化培养基获得的抗性芽在生根培养基MS+0.4 mg/L NAA+10 mg/L Km+100 mg/L Cef上进行延迟筛选,有利于获得较高的转化效率.PCR检测表明,CBF1基因已整合到菊花基因组中,共获得18株转基因植株,在抗性株系中PCR阳性率为36.7%.     

农杆菌介导的紫穗槐茎段愈伤组织遗传转化研究

采用农杆菌介导法对紫穗槐茎段诱导的愈伤组织进行遗传转化研究。确定了卡那霉素临界耐受浓度为40mg/L。菌液浓度与侵染时间的正交试验结果表明:侵染菌液OD600为0.8、侵染时间为30min时转化效率最高,达17.95%。GUS染色检测分析表明:含pBI121-GUS质粒DNA农杆菌侵染转化的愈伤组织其抗性不定芽和再生植株根和叶均呈蓝色。转化植株叶PCR检测结果表明外源GUS基因已整合到紫穗槐基因组中。以上结果表明建立了以茎段诱导愈伤组织为转化受体、农杆菌介导的紫穗槐高效遗传转化体系。为了验证其可重复性,又进行了pBI121-GFP基因的转化,T0代再生植株PCR检测整合率达85%,在488nm蓝光源激发下转化株的顶芽产生绿色荧光,说明转入的基因在35S启动子下过量表达。此遗传转化体系可应用于转基因育种。     

根癌农杆菌介导转化籼稻影响因素的研究

选用我国籼型杂交稻中的几个重要亲本 ,以携带有双元载体 p CAMBIA1 3 0 1的根癌农杆菌 EHA1 0 5为载体 ,以GUS基因的瞬间表达为依据 ,研究根癌农杆菌介导转化籼稻的影响因素 ,确立对转化频率有重要影响的几个条件。结果表明 :经短期预培养 (4～ 5d)的幼胚是较为理想的转化受体材料 ;在共培养基中添加较高浓度的乙酰丁香酮 (3 0 0～ 4 0 0μmol/ L)可提高 GUS基因的瞬间表达频率 ;以 CC培养基作为共培养后抗性愈伤筛选的基本培养基有利于抗性愈伤组织的筛选培养。按此确立的条件 ,在特青、龙特甫 (B)、珍汕 97(B)、盐恢 559等籼稻品种或亲本中的 GUS瞬间表达率高达 80 % ,抗性愈伤组织转化率高达 70 %