小麦遗传转化受体系统建立的研究

选用‘小偃22’和‘宁春16’小麦品种的成熟胚和幼胚进行培养,研究不同种类的胚和培养因子对愈伤组织诱导和分化的影响。结果表明,幼胚和成熟胚的愈伤组织诱导率无明显差异,但较高浓度的2,4-D有利于成熟胚的诱导,而幼胚培养时2,4-D浓度的影响效果因品种而异;两种外植体分化率的高低与KT/IAA的配比均有密切关系,但高浓度的激素水平不利于成熟胚的分化;诱导培养基中低浓度的2,4-D有利于所诱导的愈伤组织的分化。同时,在诱导培养基中添加低浓度的KT能显著提高两品种成熟胚愈伤组织的分化率;各种培养基处理与品种间都存在显著的互作效应,‘小偃22’成熟胚培养的最佳培养基组合为MSD 3.0 mg/L 2,4-D和MSD 0.5 mg/LIAA 1.0 mg/L KT,幼胚培养为MSD 4.0 mg/L 2,4-D和MSD 0.5 mg/L IAA 1.0 mg/L KT;‘宁春16’成熟胚培养为MSD 4.0 mg/L 2,4-D和MSD 1.0 mg/L IAA 1.0 mg/L KT,幼胚培养时为MSD 1.0 mg/L 2,4-D和MSD 2.0 mg/L IAA 2.0 mg/L KT。     

旱地小麦(金沙江一号)×天兰冰草杂种幼胚愈伤组织诱导及植株再生

旱地小麦(金沙江一号)×天兰冰草远缘杂交结实率较高,可达30.5%。但是,由于种子的胚乳发育不良而不能萌发,未获得杂种F_1实生苗,授粉12天后再把幼胚接种于WG附加2,4—D2mg/l、NAA0.5mg、K70.1mg/l培养基中,30—60%的幼胚诱导出愈伤组织。愈伤组织转入WG附加NAA0.5mg/l、KT0.5mg/l、Ad100mg/l、CH500mg/l的分化培养基后逐渐分化出丛生绿苗。这些绿苗经分根培养后移栽成活。正交和反交的杂种F_1再生植株形态呈中间类型,并且都表现了自交不孕等杂种特性。实验还比较了正交和反交的结实率及幼胚培养的愈伤组织诱导率,讨论了细胞质因子对杂种F_1幼胚再生能力的影响。     

不同杂种优势类群玉米幼胚愈伤组织的诱导及植株再生特性的研究

以Reid、唐四平头和其它种质等3个杂种优势类群共19份玉米自交系为试验材料,以玉米幼胚作为外植体,研究了基因型、培养基和激素对玉米幼胚愈伤组织的诱导及植株再生的影响,结果表明供试材料均能进行愈伤组织的诱导,但是仅有12个自交系能再生植株。N6和改良N6培养基有助于提高愈伤组织的质量及其生长速度,2,4-D在愈伤组织的诱导中起着关键性作用。在诱导培养基中添加0.2mg／L的6-BA或KT会使胚性愈伤组织的诱导频率下降以及降低愈伤组织的质量。在胚状体诱导培养基中添加1mg／L的KT能促进绿苗的分化,但是浓度过高会使丛生苗分化过多。此外,通过对不同杂种优势类群自交系玉米幼胚培养特性的分析,发现在唐四平头类群的4个自交系中,黄早四的绿苗分化率仅为0.5％,其它3个自交系不能再生植株。但是,从Reid和其它种质类群的供试自交系中筛选出了胚性愈伤组织的诱导频率和绿苗分化率均较高的、适合于遗传转化的受体材料,如3189／4380、4380／陕综5、8103、先早17、18-599红、18-599白、501、178和冀53。     

优良大麦品种花30幼胚遗传转化体系的优化

以大麦花培基因型花30的幼胚为外植体,设置不同的培养基类型、不同激素配比及碳源,研究其对幼胚愈伤组织诱导及绿苗分化的影响,以此建立和优化一个适于优良大麦品种遗传转化的高效组织培养体系。结果表明:在N6、MS和B5的组合改良培养基下,以蔗糖为碳源,附加2mg/L 2,4-D、1mg/L ABA时,有最高的愈伤组织诱导率,且愈伤质量最好。Cu2+的添加具有抑制幼胚直接发芽成苗和改善愈伤组织质量的双重功效。添加2mg/L 6-BA对愈伤组织的分化效果比较理想。为了提高农杆菌介导转化大麦外源基因的瞬时表达率和优化遗传转化体系,利用花30幼胚产生的愈伤组织为受体材料,通过检测GUS基因的瞬时表达情况,研究了农杆菌介导的大麦遗传转化中菌液的浓度、侵染时间以及共培养天数对遗传转化的影响,结果表明:当菌液浓度OD600=0.5的条件下,侵染15min,共培养2d表现出最佳的GUS瞬时表达率。     

改良MS培养基对水稻成熟胚培养的影响及其细胞组织学观察(简报)

含 5 mg/L Vit B_1,附加 2 mg/L 2,4-D,5mg/L ABA和 300 mg/L LH的MS培养基对水稻成熟胚离体培养的效果明显优于含5mg/L Vit B_1,附加2mg/L 2,4—D和1mg/LKT的MS培养基。从后者诱导产生的愈伤组织多呈白色不透明状,并通过器官(芽)发生途径再生绿苗,而前者培养基上产生的愈伤组织绝大多数为乳白色,表面呈疣状突起,常形成胚状体继而再生绿苗。     

野生稻不同外植体的离体培养

野生稻不同外植体离体培养时的幼穗愈伤组织诱导率差异在８．７％￣９４．７％之间,成熟种胚愈伤组织诱导率普遍高于幼穗,但很少能再生绿苗。野生稻幼穗直接分化培养再生绿苗率普遍高于通过愈伤组织培养分化的再生绿苗率。     

盐肤木体细胞胚胎发生及植株再生

以盐肤木(Rhus chinensis Mill.)幼胚为外植体,研究不同植物生长调节剂组合对其愈伤组织诱导及体细胞胚胎发生的影响,以建立盐肤木体细胞胚胎发生及植株再生体系。结果表明,最适愈伤组织诱导培养基为MS+6-BA 0.2 mg/L+2,4-D 1.0 mg/L,诱导率为84.57%,诱导出的初代愈伤组织白色或淡黄色,质地疏松,表面光滑,为非胚性愈伤。初代愈伤组织转移到1/2 MS+6-BA 2 mg/L+NAA 0.5 mg/L培养基上培养1个月后,长出淡黄色质地紧密的胚性愈伤组织,诱导率高达100%,在此培养基上胚性愈伤组织增殖倍数为854.73%。所获得的胚性愈伤组织转接到1/2 MS+6-BA 2 mg/L+NAA 0.5 mg/L+蔗糖4%的培养基上培养1个月后可诱导体细胞胚胎发生,诱导率可达32.67%。诱导得到的体细胞胚胎经历球形胚、心形胚、鱼雷胚、子叶胚进一步分化发育成苗。无菌苗炼苗后栽种到泥炭土∶蛭石∶珍珠岩为2∶1∶1的生长基质上,能100%稳定成活。经过细胞学观察分析,体细胞胚的发育与合子胚相似。     

球子蕨孢子的无菌繁殖

以球子蕨成熟孢子为外植体,研究了不同激素及浓度对其孢子萌发、愈伤组织诱导、丛生芽分化及生根的影响。结果表明:孢子萌发最适培养基为1/2MS+2%蔗糖,20d后萌发率达55.7%;诱导愈伤组织的最适培养基为MS+0.5mg·L-1KT+0.5mg·L-12,4-D,诱导率达36%,愈伤组织为绿色颗粒状;颗粒状愈伤组织在不添加激素的MS培养基中即可生长出大量丛生芽,转化率可达49.3%;低浓度(0.2mg·L-1)的IAA可有效促进幼孢子体苗生根。     

籼稻花药培养研究——Ⅰ.基本培养基及附加成分在诱导籼稻花药产生愈伤组织及根芽分化中的作用

对6个籼稻(oryza sativa Subsp.Shien)品种和39个籼×籼杂种的花药在离体条件下进行培养,有5个品种及35个杂种得到了愈伤组织,平均诱导率为2.18％。在3个品种及11个籼×籼杂种中得到了绿苗或绿芽。本文着重报道基本培养基及其附加成分在诱导籼稻花药产生愈伤组织及根芽分化中的作用。 1.试验了几种诱导愈伤组织的培养基,以Miller培养基 2,4—D2毫克/升 酵母浸出液1,000毫克/升 激动素1毫克/升 吲哚乙酸2毫克/升 椰乳15％为最好。诱导率高者可达11—15％,平均诱导率在3％以上。 2.Ms、Nitsch及Miller培养基均可诱导籼稻花药愈伤组织分化出绿色的花粉植株。 3.籼稻花药愈伤组织的分化,随着激动素/生长素比值的增高,绿苗分化率及总分化率均有提高的趋势。而粳稻的这种关系不甚明显。 4.Miller培养基附加2毫克/升的吲哚乙酸对促进具茎、叶而无根的籼稻花粉小植株产生根有很好的作用。在这种培养基上,不仅可以诱导根的发生,而且根系发达,生长较弱的苗转移到这种培养基后,因根系健壮,生势好,转入盆栽,基本可以全部成活。     

紫果猕猴桃幼胚愈伤组织诱导及植株再生

以紫果猕猴桃(Actinidia arguta var．purpurea)幼胚为外植体,诱导愈伤组织并进行植株再生。结果表明：不同的培养基和不同的培养条件对幼胚愈伤组织的诱导率及分化率不同;0．2mg／L ZT与0．5mg／L GA。配合使用有利于促进愈伤组织的诱导;7％蔗糖、600mg／L CH与400mg／L Gln都有利于促进愈伤组织的形成;在添加0．5mg／L 6-BA、0．05mg／L NAA与0．5mg／L GA3的MS培养基中植株的再生率达93．3％。     

Screening Wheat Genotypes for High Callus Induction and Regeneration Capability from Immature Embryo Cultures

Selecting the explant genotypes is crucial step in in vitro culture and Agrobacterium-mediated transformation system due to its host range specificity. Immature embryos of five winter and three spring wheat (Triticum aestivum L) cultivars were evaluated for tissue culture response in three callus initiation media. MS medium containing 2,4-0 (2 mg ml^-1) plus B5 vitamins (MSB5), MS medium containing 2,4-0 (1 mg ml^-1) with no vitamins (MS1GC) or MS medium containing picloram (2.2 mg ml^-1) and 2,4-0 (0.5 mg ml^-1) plus MS vitamins (CM4C) were used for callus initiation. Percentage of callus induction varied widely with the genotype and initiation medium used, with values ranging from 5.7% to 100%. Embryogenic capacity of genotypes was evaluated by number of somatic embryos formed from cultured immature embryos. Bob White (spring) and NE92458 (winter) were equal and most embryogenic; Pronghorn and 2137 (both winter) were the poorest. CM4C medium was found to be the best medium for initiating embryogenic callus among three culture media tested. A standard regeneration procedure was used. The genotypes with the highest regeneration efficiencies were Bob White, Fielder and NE92458, (1.8, 1.4 and 1.6 plantslexplant, respectively).     

Efficient callus induction and plant regeneration from mature embryo culture of winter wheat (Triticum aestivum L.) genotypes

Immature and mature embryos of 12 common winter wheat (Triticum aestivum) genotypes were cultured in vitro to develop an efficient method of callus formation and plant regeneration from mature embryo culture, and to compare the responses of both embryo cultures. Fifteen days after anthesis, immature embryos were aseptically dissected from seeds and placed with the scutellum upwards on a solid agar medium containing the inorganic components of Murashige and Skoog (MS) and 2 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D). Mature embryos were moved slightly in the imbibed seeds. The seeds with moved embryos were placed furrow downwards in dishes containing 8 mg/l 2,4-D for callus induction. The developed calli and regenerated plants were maintained on 2,4-D-free MS medium. Plants regenerated from both embryo cultures were vernalized and grown to maturity in soil. Regenerated plantlets all maintained the hexaploid chromosome number. A strong genotypic effect on the culture responses was found for both explant cultures. Callus induction rate, regeneration capacity of callus and number of plants regenerated were independent of each other. Mature embryos had a high frequency of callus induction and regeneration capacity, and therefore, being available throughout the year, can be used as an effective explant source in wheat tissue culture. Received: 4 February 1997 / Revision received: 1 April 1997 / Accepted: 5 May 1997     

人工合成冬性六倍体小麦的研究

以冬性四倍体硬粒小麦(Triticum durum,2n=28,AABB)为母本与粗山羊草(Aegilops tauschii,2n=14,DD)杂交,得到的单倍体幼胚(n=21,ABD)经组织培养拯救,获得的幼苗经染色体加倍而成为合成小麦(AABBDD)。从中鉴定、筛选出冬性的合成小麦。幼胚仅在1/2 MS培养基上培养,成苗率为75.81%;根据幼胚的发育状态,将发育较完善的幼胚直接接种在1/2 MS培养基上,将发育不良的幼胚先接种于1/2 MS+2 mg/L 2,4-D培养基上进一步养育幼胚,之后视幼胚发育状况再将其转入1/2 MS培养基中培养成苗,此方法的成苗率为92.44%,较前者的成苗率提高了16.63%。染色体加倍在冬季塑膜拱棚内用0.05%秋水仙素进行半根法处理,较容易获得健壮苗,并且分蘖多。     

提高小麦基因枪法转化频率的研究

用基因枪法将带Ｂａｒ－ＧＵＳ双标记基因的质粒较入普通春小麦品种中－６０６３４的幼胚盾片,并获基因植株。在轰击的经预培养３－４天的３４２块幼胚片再经筛选再生的植株中,经ＰＣＲ和Ｓｏｕｔｈｅｒｎ分析表明,     

外源脱水应答转录因子DREB基因在转基因小麦中的诱导型表达与抗干旱生理效果研究

以冬小麦品种8901、5-98、99-92和104等品种的幼穗和幼胚为材料,用基因枪转化含逆境诱导转录因子DREB和bar基因的质粒pBAC128F（7024bp）。经筛选与植株再生,共获得70多个转基因小麦植株及其后代株系。转基因株系经PCR分析和RNA点杂交检测,结果表明外源转录因子DREB基因已稳定整合到转基因植株及其后代株系中,并且在部分后代株系中获得了表达。叶片脯氨酸含量测定表明,有16个转基因株系的脯氨酸含量与非转基因对照相比,增加相当显著,其中10个株系的脯氨酸含量在1100μg/g以上,比对照提高了2倍多。室内抗旱模拟实验表明,转基因株系停止浇水15d后,叶片仍然表现绿色,而对照叶片则失绿、枯干;复水10d后,转基因株系恢复活力,对照则死亡。研究表明,利用逆境诱导型启动子（rd29B）来增强外源DREB基因的表达,能显著改良小麦的抗旱性。     

Optimization of Agrobacterium-mediated transformation in spring bread wheat using mature and immature embryos

Wheat is the most widely grown staple food crop in the world and accounts for dietary needs of more than 35% of the human population. Current status of transgenic wheat development is slow all over the world due to the lack of a suitable transformation system. In the present study, an efficient and reproducible Agrobacterium-mediated transformation system in bread wheat (Triticum aestivum L.) is established. The mature and immature embryos of six recently released high yielding spring bread wheat genotypes were used to standardize various parameters using Agrobacterium tumefaciens strain EHA105 harbouring binary vector pCAMBIA3301 having gus and bar as marker genes. The optimum duration for embryo pre-culture, inoculation time and co-cultivation were 2 days, 30 min and 48 h, respectively. The bacterial inoculum concentration of OD of 1 at 600 nm showed 67.25% transient GUS expression in the histochemical GUS assay. The filter paper based co-cultivation limits the Agrobacterium overgrowth and had 82.3% explants survival rate whereas medium based strategy had 22.7% explants survival only. The medium having picloram 4 mg/l along with antibiotics (cefotaxime 500 mg/l and timentin 300 mg/l) was found best suitable for initial week callus induction. The standardized procedure gave overall 14.9% transformation efficiency in immature embryos and 9.8% in mature embryos and confirmed by gene-specific and promoter-specific PCR and southern analysis. These results indicate that the developed Agrobacterium-mediated transformation system is suitable for diverse wheat genotypes. The major obstacle for the implication of the CRISPR-based genome editing techniques is the non-availability of a suitable transformation system. Thus, the present system can be exploited to deliver the T-DNA into the wheat genome for CRISPR-based target modifications and transgene insertions.

     

花生体细胞胚的诱导及其植株再生

采用不同成熟度的花生胚轴为外植体进行体细胞胚诱导及植株再生研究,结果表明,成熟胚轴在高浓度2,4－D的MS培养基中,经过30d左右的培养,可直接诱导产生出大量的体细胞胚,含40mgL~－12,4－D的培养基中体细胞胚的诱导率达100％,平均每个外植体产生11．58个体细胞胚．体细胞胚的继代培养需降低2,4－D的浓度（1－20mgL~－1）．未成熟胚轴的体细胞胚诱导及继代培养的2,4－D浓度宜为10mgL~－1．将诱导的体细胞胚转接到合5－10mgL~－1BA的MS培养基中,体细胞胚能够萌发再生成无根小植株,将其转接到生根培养基中可获得完整小植株．     

用基因枪法将人工雄性不育基因导入小麦的研究初报

利用ＰＤＳ１０００／氦气基因枪将人工构建的雄性不育基因（ＴＡ２９－Ｂａｒｎａｓｅ基因）导入小麦栽培品种豫责１８号的幼胚细胞。然后在含有１０～２０ｍｇ／Ｌ除草剂Ｂａｓｔａ的培养基础上筛选与分化。从１７０个幼胚中获得６株绿苗,对照的７０个幼胚中未得到绿苗。对其中３株已生根且长势好的绿苗进行Ｓｏｕｔｈｅｍ杂交分析,结果表明,这３株绿苗皆为转基因植株,转化效率达１．８％。     

The effect of auxins, time exposure to auxin and genotypes on somatic embryogenesis from mature embryos of wheat

The effects of different factors on the embryogenesis and plant regeneration from mature embryos of Russian spring and winter genotypes were studied. Embryogenic callus induction was achieved on MS medium supplemented with different concentrations of 2,4-D (2,4-dichlorophenoxyacetic acid), 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) or Dicamba (3,6-dichloro-o-anisic acid). Although all auxins were able to induce callus from explants with high frequency (98–100%), Dicamba was more effective for the induction of embryogenic callus (21.8–38.3%). Maximum embryogenic callus formation and high number of regenerated plants were observed at 12 mg l⁻¹ of Dicamba. The time exposure to Dicamba (7, 14, 21 and 28 days) had a significant effect on efficiency of somatic embryogenesis. When contact of explants with callus induction medium was increased from 7 to 21 days the rate of somatic embryogenesis and number of regenerated plants per embryogenic callus gradually increased from 13.0 to 38.4% and 3.6 to 8.0%, respectively. Supplement of additional auxins (indoleacetic acid (IAA), indolebutyric acid (IBA), and naphthaleneacetic acid (NAA)) to callus induction medium with Dicamba had a positive effect on the rate of embryogenic callus formation, while the average number of regenerated shoots was not affected. The best rate of somatic embryogenesis was observed at the addition of 0.5 mg l⁻¹ IAA with Dicamba (61.0%). The optimum combination of Dicamba and IAA increased the efficiency of somatic embryogenesis and plant regeneration from seven spring and winter wheat genotypes, thought overall morphogenic capacity was still genotype dependent.