带内含子卡那霉素抗性基因双元载体构建及烟草转化

农杆菌介导法是植物基因转化的常用方法,然而由于筛选培养基中常用的抗生素头孢霉素和羧苄青霉素具有类植物激素活性,影响外植体的再生和转化频率,将一个植物的内含子插入卡那霉素抗性基因编码区的N端。合成了一个带内含子的卡那霉素抗性基因。构建带该基因的植物双元表达载体pYP1202并转化烟草,受外植体在含卡那霉素50－200mg/L的选择培养基中抗性芽分化频率不受卡那霉素浓度影响,然而具有GUS活性的转化子占分化芽的比例却随着卡那霉素浓度的增加而升高。当培养基中加入500mg/L羧苄青霉素后受侵外植体产生的抗性芽频率比单一的卡那霉素筛选提高近1倍,高达91.4％,然而具GUS活性的转化子占抗性芽的比较仅有26.7％,在200mg/L的卡那霉素筛选下,比例升至93.3％。用带内含子卡那霉素抗性基因构建的植物表达载体转化植物可以减少假抗性芽的产生。     

农杆菌介导的紫茎泽兰遗传转化研究

以紫茎泽兰为受体材料,GUS基因为报告基因,对农杆菌介导的遗传转化条件及影响因素进行研究,建立了农杆菌介导的紫茎泽兰遗传转化体系。结果表明,将未经过预培养的幼叶外植体在OD600为0.4的稀释菌液中浸泡12min,共培养3d后,转移到加有卡那霉素50mg/L(筛选压)和羧苄青霉素250mg/L的分化培养基上,经过20d外植体直接分化出不定芽,诱导生根成苗。经PCR和组织化学染色鉴定,可稳定获得较高的阳性转化率。     

胡杨遗传转化体系的建立及抗生素浓度的优化

探讨了不同激素浓度对胡杨叶片分化以及卡那霉素、G418、羧苄青霉素和头孢霉素4种抗生素对胡杨不同培养阶段外植体生长、分化或生根的影响,确定了由农杆菌介导的胡杨遗传转化研究中抗生素种类和转化体的筛选浓度,建立了适于胡杨叶片转化的遗传转化体系。结果表明:胡杨叶片再生的最佳培养基为MS+BA0.5mg/L+NAA0.1～0.2mg/L+白砂糖25g/L+琼脂5g/L;在叶片转化筛选阶段,卡那霉素和G418的适宜浓度分别为10mg/L和7.5mg/L,羧苄青霉素和头孢霉素的适宜浓度为200～600mg/L和200～400mg/L;在抗性芽生根培养时,卡那霉素和G418分别为15～20mg/L和10～15mg/L,羧苄青霉素和头孢霉素为200～800mg/L和200～600mg/L。     

中国传统菊花品种‘小林静’再生及转化体系的建立

以中国传统菊花品种‘小林静’叶片为外植体,建立了‘小林静’较好的再生体系及遗传转化体系.结果表明,‘小林静’叶盘最适不定芽分化培养基为MS+2.0 mg/L 6-BA+1.5 mg/L NAA,不定芽分化率为92.76％,平均再生不定芽数为2.3767个;试管苗最佳生根培养基为1/2MS,生根率达100％.移栽采用灭菌的蛭石,再生苗移栽成活率达90％以上.采用根癌农杆菌C58C1介导的叶盘转化法进行‘小林静’的遗传转化试验,农杆菌OD600=0.5-0.6,侵染10 min后,将叶片外植体接种到MS+2.0 mg/L 6-BA+1.5mg/L NAA的培养基中黑暗共培养2d,之后转接到附加10 mg/L硫酸卡那霉素和400 mg/L羧苄青霉素的分化筛选培养基中进行转化细胞的筛选,待长出抗性芽后转接至生根培养基中进行培养,最终建立了菊花品种‘小林静’的遗传转化体系.     

"全明星"草莓叶片遗传转化体系的建立

采用根癌农杆菌介导法进行nptⅡ基因对全明星草莓叶片的遗传转化研究,对转化过程中的一些因素进行了探讨：全明星叶片对卡那霉素的敏感实验,得出最适筛选浓度为30mg／L,羧苄青霉素的最适抑菌浓度为450mg／L;50μmol／L乙酰丁香酮(AS)的加入可提高GUS的瞬时表达率;10～15min是最适合叶片侵染的时间;共培养3d对叶片转化较适宜,得到抗卡那霉素的抗性芽的频率为1．1％,初步鉴定是转化芽。为草莓的遗传转化奠定基础。     

根癌农杆菌对甘蓝型油菜的转化及转基因植株的再生

用根癌农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍ ｅｆａｃｉｅｎｓ）共培养法把外源基因导入甘蓝型油菜（Ｂｒａｓｓｉ－ｃａ ｎａｐｕｓＬ．）主要栽培品种“云北２ 号”,获得转基因植株。所用外植体为带有１—２ ｍ ｍ 子叶柄的完整子叶,根癌农杆菌为Ａ２０８ＳＥ（ｐＴｉＴ３７－ＳＥ, ｐＲＯＡ９３）。Ｔｉ质粒ｐＲＯＡ９３ 带有ＮＰＴⅡ及ＧＵＳ嵌合基因。共培养２ 天后转到附加２５ ｍ ｇ／Ｌ卡那霉素的分化培养基（ＭＳ＋ ４．５ ｍ ｇ／ＬＢＡＰ）上。ＡｇＮＯ３ 和羧苄青霉素促进芽的分化,头孢霉素则有抑制作用。最高转化频率为２７％ 。把分化出的茎芽切下,插入含有２５ ｍ ｇ／Ｌ卡那霉素的生根培养基中。羧苄青霉素不利于根的形成。把完整抗性植株移入盛土壤的盆中,生长状况良好。测定β－葡糖苷酸酶活性,８４％ 明显高于对照。以ＮＰＴⅡ基因作探针进行Ｓｏｕｔｈｅｒｎ ｂｌｏｔ分析,证实外源基因已插入到植物细胞基因组中     

根癌农杆菌对巴戟天遗传转化的影响因素

以巴戟天带节茎为材料,研究了根癌农杆菌对巴戟天遗传转化的影响因素。结果表明:外植体感染前先进行2 d预培养,对转化有一定促进作用;外植体与农杆菌共培养时间以3 d为宜;乙酰丁香酮能提高转化效率,抗性芽分化率可达18.0％;外植体与农杆菌共培养后延迟4 d选择,抗性芽分化率有所提高;硝酸银能抑制外植体表面农杆菌的生长,提高GUS阳性芽的比例,硝酸银浓度2 mg/L时,GUS阳性芽比例最高(42.9％)。     

抗虫转基因甘蓝及其后代的研究

通过农杆菌感染法将苏云金杆菌杀虫蛋白基因转移进了甘蓝的基因组,带子叶柄的子叶作为外植体与农杆菌共培养.发生在子叶柄基部的愈伤组织在含卡那霉素(Km)15～30mg/L的MS培养基上进行筛选,约5%外植体上的愈伤组织继续长大,当移到含Km和6-BA的分化培养基上时,愈伤组织分化出绿色的芽.将芽分离培养,约80%在加有Km的培养基上被诱导生了根.未转化的对照组织在筛选培养基上不能分化出正常的芽和根系,并且逐渐褐化死亡.小菜粉蝶的幼虫被饲喂以转基因植株的叶片,幼虫出现中毒症状,表现为发育受阻和死亡.约20%受试植物的DNA与苏云金杆菌杀虫蛋白基因探针杂交显阳性带.由转基因植株的种子长成的第2代甘蓝幼苗的卡那霉素抗性和植株的抗小菜粉蝶的活力均符合孟德尔单基因分离规律.     

农杆菌介导的橡胶草遗传转化体系的建立

以橡胶草为试验材料,利用农杆菌介导法进行遗传转化研究。结果表明：50 mg/L的卡那霉素(Kan)对橡胶草的抗性芽具有很好地筛选效果,生根筛选时,Kan的适宜质量浓度为35 mg/L;最佳抑菌抗生素为羧苄青霉素（cb）,适宜质量浓度为500 mg/L,获得35株抗性试管苗,通过GUS染色及分子生物学检测,最终获得6株转基因植株,转化率为17.1%。可见,获得的橡胶草转基因植株,为橡胶草后续的遗传转化研究奠定了基础。     

根癌农杆菌介导D32基因

以烟草品种'中烟99'的无菌苗叶片为转化受体材料,通过根癌农杆菌C58C1介导对大豆中克隆的抗逆性基因D32进行转化,获得了抗卡那霉素的再生植株,并对转化植株进行了PCR检测.结果表明,烟草叶片分化和再生的卡那霉素选择压力为150 mg/L;外植体预培养对转化率有影响;优化的烟草转化方法是:经预培养2 d的外植体用OD600值为0.7的菌液侵染5 min, 共培养2 d后用无菌水冲洗5～6次,羧苄青霉素(Cb)和头孢霉素(Cef)浓度为400 mg/L的脱菌液浸泡120 min,超净工作台上吹风60 min,于筛选分化培养基生长50 d,可获得26.7%卡那抗性苗.对抗性植株经PCR检测证明,外源D32基因已初步整合到烟草基因组中.     

农杆菌介导红江橙遗传转化的研究初报

用红江橙实生苗的上胚轴为材料 ,初步研究以根癌农杆菌介导的 GUS基因转化。结果表明 :以卡那霉素作为选择试剂进行选择培养时 ,Km浓度为 5 0 mg/L;外植体以平放为好 ;抑菌剂选择头孢霉素较好。GUS基因瞬时表达检测 ,70 .4%的外植体呈阳性反应 ;GUS基因稳定表达检测 ,在获得的 1 2株抗性植株中 ,GUS反应呈阳性所占比例为 1 6.7%。     

根癌农杆菌介导GUS基因对白桦转化的研究

本文报道了根癌农杆菌介导GUS基因转化白桦叶盘的研究方法,对转化过程中各种因素进行了全面探讨,结果表明:白桦叶盘对卡那霉素的敏感实验,得出最适筛选浓度为50mg/l;对头孢霉素和羧苄青霉素的抑菌实验,最适抑菌浓度为500mg/l;100μMAS的加入可将抗性不定芽的诱导率提高3倍;3~4d的预培是最适合叶盘转化的时间;10~20min是最适合叶盘浸染的时间;3~4d的共培养对于叶盘转化比较合理。在上述最适合的转化条件下,农杆菌介导的GUS基因对白桦叶盘的转化获得了抗性再生植株,转化率为2.8%。     

A High Efficient Transformation System and the Introduction of Sweet Protein Gene into Potato (Solanum tuberosum L.)

Tuber, minituber and in vitro-grown microtuber discs of potato (Solanum tuberosum L.) cultivars 85-14-3, 86-2 and Favorita were used in Agrobacterium mediated gene transfer. A simple, rapid and efficient transformation system was established. Among the three kinds of discs used, the microtuber disc was superior in obtaining transformants. Microtuber discs star ted to form shoots on shoot inducing medium containing kanamycin two to three weeks after cocultivation. Rooted transformants could be obtained in 6–7 weeks. The transformation efficiency could reach as high as 67.5%. The majority of kanamycin resistant plants gave nopaline positive or GUS expression. A number of transgenic plants were obtained using the plasmid containing a sweet protein NPT Ⅱ and nopaline synthase genes. The leaf callus assay and nopaline assay indicated that the foreign sweet protein gene was introduced into the potato genome.     

<Emphasis Type="Italic">Agrobacterium tumefaciens</Emphasis>-mediated transformation of eggplant (<Emphasis Type="Italic">Solanum melongena</Emphasis> L.) using root explants

An efficient variety-independent method for producing transgenic eggplant (Solanum melongena L.) via Agrobacterium tumefaciens-mediated genetic transformation was developed. Root explants were transformed by co-cultivation with Agrobacterium tumefaciens strain LBA4404 harbouring a binary vector pBAL2 carrying the reporter gene beta-glucuronidase intron (GUS-INT) and the marker gene neomycin phosphotransferase (NPTII). Transgenic calli were induced in media containing 0.1 mg l(-1) thidiazuron (TDZ), 3.0 mg l(-1) N(6)-benzylaminopurine, 100 mg l(-1) kanamycin and 500 mg l(-1) cefotaxime. The putative transgenic shoot buds elongated on basal selection medium and rooted efficiently on Soilrite irrigated with water containing 100 mg l(-1) kanamycin sulphate. Transgenic plants were raised in pots and seeds subsequently collected from mature fruits. Histochemical GUS assay and polymerase chain reaction analysis of field-established transgenic plants and their offsprings confirmed the presence of the GUS and NPTII genes, respectively. Integration of T-DNA into the genome of putative transgenics was further confirmed by Southern blot analysis. Progeny analysis of these plants showed a pattern of classical Mendelian inheritance for both the NPTII and GUS genes.     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated genetic transformation of <Emphasis Type="Italic">Perilla frutescens</Emphasis>

A reproducible plant regeneration and an Agrobacterium tumefaciens-mediated genetic transformation protocol were developed for Perilla frutescens (perilla). The largest number of adventitious shoots were induced directly without an intervening callus phase from hypocotyl explants on MS medium supplemented with 3.0 mg/l 6-benzylaminopurine (BA). The effects of preculture and extent of cocultivation were examined by assaying -glucuronidase (GUS) activity in explants infected with A. tumefaciens strain EHA105 harboring the plasmid pIG121-Hm. The highest number of GUS-positive explants were obtained from hypocotyl explants cocultured for 3 days with Agrobacterium without precultivation. Transgenic perilla plants were regenerated and selected on MS basal medium supplemented with 3.0 mg/l BA, 125 mg/l kanamycin, and 500 mg/l carbenicillin. The transformants were confirmed by PCR of the neomycin phosphotransferase II gene and genomic Southern hybridization analysis of the hygromycin phosphotransferase gene. The frequency of transformation from hypocotyls was about 1.4%, and the transformants showed normal growth and sexual compatibility by producing progenies.     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of niger [<Emphasis Type="Italic">Guizotia abyssinica</Emphasis> (L. f.) Cass.] using seedling explants

A protocol was developed for Agrobacterium-mediated genetic transformation of niger [ Guizotia abyssinica (L.f.) Cass.] using hypocotyl and cotyledon explants. Hypocotyls and cotyledons obtained from 7-day-old seedlings were co-cultivated with Agrobacterium tumefaciens strain EHA101/pIG121Hm that harbored genes for beta-glucuronidase (GUS), kanamycin, and hygromycin resistance. Following co-cultivation, the hypocotyl and cotyledon explants were cultivated on MS medium containing 1 mg/l 6-benzylaminopurine (BA) for 3 days in darkness. Subsequently, hypocotyl and cotyledon explants were transferred to selective MS medium containing 1 mg/l BA, 10 mg/l hygromycin, 10 mg/l kanamycin, and 500 mg/l cefotaxime. After 6 weeks, hypocotyls and cotyledons produced multiple adventitious shoot buds, and these explants were subcultured to MS medium containing 1 mg/l BA, 30 mg/l hygromycin, and 30 mg/l kanamycin. After a further 3 weeks, the explants (along with developing shoot buds) were subcultured to MS medium containing 1 mg/l BA, 50 mg/l kanamycin, and 50 mg/l hygromycin for further selection. Transgenic plants were obtained after rooting on half-strength MS medium supplemented with 0.1 mg/l alpha-naphthaleneacetic acid, 50 mg/l kanamycin, and 50 mg/l hygromycin and were confirmed by GUS histochemical assay and polymerase chain reaction analysis. Genomic Southern blot hybridization confirmed the incorporation of the neomycin phosphotransferase II gene into the host genome.     

Agrobacterium mediated transformation of chickpea (Cicer arietinum L.) embryo axes

 Embryo axes of four accessions of chickpea (Cicer arietinum L.) were treated with Agrobacterium tumefaciens strains C58C1/GV2260 carrying the plasmid p35SGUSINT and EHA101 harbouring the plasmid pIBGUS. In both vectors the GUS gene is interrupted by an intron. After inoculation shoot formation was promoted on MS medium containing 0.5 mg/l BAP under a selection pressure of 100 mg/l kanamycin or 10 mg/l phosphinothricin, depending on the construct used for transformation. Expression of the chimeric GUS gene was confirmed by histochemical localization of GUS activity in regenerated shoots. Resistant shoots were grafted onto 5-day-old dark-grown seedlings, and mature plants could be recovered. T-DNA integration was confirmed by Southern analysis by random selection of putative transformants. The analysis of 4 plantlets of the T1 progeny revealed that none of them was GUS-positive, whereas the presence of the nptII gene could be detected by polymerase chain reaction. Received: 30 May 1997 / Revision received: 18 September 1997 / Accepted: 22 March 1999     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) via vacuum infiltration

AnAgrobacterium-mediated gene transfer system with recovery of putative transformants was developed for cotton (Gossypium hirsutum L.) cv. Cocker-312. Two-month-old hypocotyl-derived embryogenic calli were infected through agroinfiltration for 10 min at 27 psi in a suspension ofAgrobacterium tumefaciens strain GV3101 carrying tDNA with theGUS gene, encoding β-glucuronidase (GUS), and the neomycin phosphotransferase II (nptII) gene as a kanamycin-resistant plant-selectable marker. Six days after the histochemicalGUS assay was done, 46.6% and 20%GUS activity was noted with the vacuum-infiltration and commonAgrobacterium-mediated transformation methods, respectively. The transformed embryogenic calli were cultured on selection medium (100 mg/L and 50 mg/L kanamycin for 2 wk and 10 wk, respectively) for 3 mo. The putative transgenic plants were developed via somatic embryogenesis (25 mg/L kanamycin). In 4 independent experiments, up to 28.23% transformation efficiency was achieved. PCR amplification and Southern blot analysis fo the transformants were used to confirm the integration of the transgenes. Thus far, this is the only procedure available for cotton that can successfully be used to generate cotton transformants.     

酚类化合物促进含双元载体农杆菌对胡萝卜悬浮细胞的转化和植株再生

含双元载体的非致瘤根癌农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍ ｅｆａｃｉｅｎｓ） ＬＢＡ４４０４经乙酰丁香酮和复合酚类化合物活化预处理后,感染胡萝卜（Ｄａｕｃｕｓ ｃａｒｏｔａ）悬浮培养细胞,在含５０ ｍ ｇ／ＬＫｍ 的选择培养基上筛选Ｋｍ ｒ 克隆。实验表明：酚类化合物活化预处理组的转化率分别为０．２４％ 和０．１７％ ,而未经酚类化合物活化处理组的转化率仅为０．０２％ 。Ｋｍ ｒ 克隆在含５０ ｍ ｇ／Ｌ Ｋｍ 的无激素培养基上通过体细胞胚胎发生形成完整植株。组织化学分析表明：报告基因ＧＵＳ的活性可出现于Ｋｍ ｒ 克隆细胞、再生植株的根、茎、叶、叶柄维管束薄壁细胞、叶片的气孔保卫细胞、皮层细胞、叶肉细胞和毛状体、叶柄的表皮细胞和表皮下薄壁细胞