发根农杆菌Ri质粒rolB基因研究进展（综述）

RiT-DNArolB基因是发根农杆菌转化植物的决定因子,rolB基因表达引起转基因植物形成大量毛状根（hairy root)。本文介绍近年来rolB基因的位点,表达与调控及RolB蛋白结构与功能方面的研究进展。     

发根农杆菌Ri质粒的分子生物学及其应用前景

发根农杆菌(Agrobacterium rhizogenes)与根癌农杆菌(Agrobacterium tumefaci-end)均是革兰氏阴性菌,同属根瘤菌科(Rhizobaceae)。根癌农杆菌侵染可以诱使大多数双子叶植物产生冠癌瘤(crown gall),发根农杆菌则可以使植物宿主细胞组织产生毛状根瘤(hairy roots tumors)。土壤杆菌的这一类致病特性早在本世纪初就已被观察     

发根农杆菌Ri质粒在药用植物生物工程中的应用

发根农杆菌(Ａｇｒｏｂａｃｔｅｒｉｕｍｒｈｉｚｏｇｅｎｅｓ)与根癌农杆菌(Ａ.ｔｕｍｅｆａｃｉｅｎｓ)属于根瘤菌科,均为革兰氏阴性菌[1]。它们在侵染植物后引起的症状不同,含有Ｔｉ质粒的根癌农杆菌在侵染植物后形成冠瘿瘤(ｃｒｏｗｎｇａｌｌ),而含有Ｒｉ质粒的发根农杆菌表现与其不同,它在感染植物后在植物的伤口部位诱发产生毛状根(ｈａｉｒｙｒｏｏｔ)。由发根农杆菌侵染植物诱导产生的毛状根具有生长快、分枝多、根毛多等特点。发根农杆菌Ｒｉ质粒与根癌农杆菌Ｔｉ质粒结构相似,都具有高效率转移的Ｔ-ＤＮＡ区和致病的Ｖｉｒ区…     

发根农杆菌Ri质粒及其在植物科学中的应用

阐述了发根农杆菌的性质及Ri质粒的结构和功能,介绍了毛状根的诱导及其鉴定方法,并对Ri质粒在植物基因工程、植物次生代谢产物生产、植物品种改良和植物栽培等方面的应用进行了综述。     

发根土壤杆菌Ri质粒对黄瓜进行遗传转化的研究

以发根土壤杆菌Ｒｉ质粒介导,对载体ｐＢＴＣ－８上的Ｔ－ＤＮＡ转化黄瓜进行了初步研究。采用黄瓜的各种不同外植体片断与土壤直菌共培养的方法,诱导出具有典型毛状根特性的转化根,转化根经诱导培养形成愈伤组织,冠瘿碱检测表明,转化根及愈伤组织含有农杆碱和甘露碱。愈伤组织进一步分化培养再生出完整植株。再生植株表现卡那霉素抗性。     

发根农杆菌Ri质粒及其应用

土壤微生物(Agrobacterium)的作用引起人们的极大兴趣。Agrobacterium与根瘤菌(Rhizobium)接近,同属于根瘤菌科,为革兰氏阴性菌。同属内已知有引起不同病征的许多种类。     

发根农杆菌Ri质粒rol基因研究进展及在林木改良上的应用

Ri质粒上携带的诱根基因的表达不仅能导致植物被感染部位形成大量的毛根,而且由毛根容易获得再生的转化植株,这些植株可表现出许多能稳定遗传的表型变异,在植物遗传改良中有着广阔的应用前景。20世纪80年代以来,国内外学者对发根农杆菌Ri质粒及其rol基因进行了广泛深入的研究。本文重点综述了农杆碱型发根农杆菌Ri质粒的结构与功能,rol基因的位点与特征,Ri质粒的转化与rol基因的表达对植物生长发育的影响及在林木遗传改良上应用等方面的研究现状,并讨论了Ri质粒rol基因在林木遗传改良应用上存在的问题与应用前景。     

发根农杆菌及其应用

农杆菌是一类侵染性非常广泛的Ｇ-土壤杆菌,农杆菌质粒介导的基因转移系统是植物基因工程中比较完善与有效的基因转移方法。在众多的转基因植物中有80%是由农杆菌介导转化的,但其中大部分是有根癌农杆菌Ｔｉ质粒介导法获得的。根癌农杆菌含有的Ｔｉ质粒,能诱导被侵染的植物细胞形成肿瘤,即诱发冠瘿瘤。发根农杆菌含有Ｒｉ质粒,侵染植物后能诱发植物细胞产生毛发状根,即发根瘤。近年来的研究发现发根农杆菌Ｒｉ质粒介导法比Ｔｉ质粒法具有一定优越性而被广泛重视,而且由其转化获得转基因植物和生物有效成分的报道愈来愈多,本文主要讨论发根农…     

Ri质粒诱导的植物发根培养系及其应用

阐述了具Ri质粒的发根农杆菌的生物学特性,介绍了毛状根的诱导、筛选及增殖培养的具体方法,提出了农杆菌转化植物细胞的影响因素,对国内外利用植物发根培养系进行次生代谢物质生产方面的研究进行了综述,并对Ri质粒诱导的发根培养系的应用作了展望。     

发根土壤杆菌在植物次生代谢物生产中的应用与进展

发根土壤杆菌 (Agrobacteriumrhizogenes)是一类极具应用前景的微生物资源 ,就发根土壤杆菌Ri质粒结构、功能、侵染和致病过程及其宿主、转化体特性进行了概述 ,并详细讨论了发根土壤杆菌在生产植物次级代谢产物方面的应用与进展及相关影响因素 ,同时还简单介绍了工业化生产的培养方法、生物反应器种类及存在的问题与困难。     

发根农杆菌介导的药用植物遗传转化研究

利用发根农杆菌(Agrobacterium rhizogenes)诱导药用植物产生的毛状根具有生长迅速,合成能力强和遗传性稳定等优点,已成为一种新的培养系统。就影响发根农杆菌介导的药用植物遗传转化的因素作一概述。     

Tobacco plants were transformed by Agrobacterium rhizogenes infection during their evolution

We discovered that the origin of cT-DNA in the genome of wild-type Nicotiana glauca is the T-DNA of the mikimopine-type Ri plasmid (pRi) harbored in Agrobacterium rhizogenes. The cT-DNA was inserted into the genomic DNA of N. glauca from the position corresponding to the right border of mikimopine-type pRi. The cT-DNA contained two mikimopine synthase gene (mis) homologs, NgmisL and NgmisR, both of which were transcribed at low level in all N. glauca organs. NgMisR protein expressed in Escherichia coli has preserved Mis activity, which converts l-histidine and alpha-ketoglutaric acid to mikimopine. The mis homolog was also found in the genome of three other Nicotiana species: N. tomentosa, N. tomentosiformis, and N. tabacum; however, the site of insertion differed from that in N. glauca, suggesting that A. rhizogenes harboring mikimopine-type pRi independently infected the ancestors of some Nicotiana plants. This is the first clear evidence of a host-parasite relationship during the early evolution of Nicotiana plants. We propose that a new phylogenetic approach using opine type cT-DNA is applicable for presuming divergence in the genus Nicotiana.     

用农杆菌Ri诱导蒙古黄芪发根培养的研究

用蒙古黄芪(Astragalus membranaceus Bunge var mongolicus (Bunge) Hsiao) 无菌籽苗的不同部位作为外植体, 用发根农杆菌(Agrobacterium rhizogenes) R1601进行感染, 该品系对不同外植体诱导毛状根的能力是不同的。由下胚轴成功的诱导出毛状根。在附加100μmol/L乙酰丁香酮(acetosyringone)、0 3 mg/L IBA的条件下, 诱导率达42 2%。用硅胶薄层层析法检测到毛状根中含有冠瘿碱, 用硅胶薄层扫描法(TLCS) 测定了蒙古黄芪野生根、栽培根及毛状根中的黄芪甲甙( astragaloside IV) 含量, (用黄芪甲甙标准品作对照), 它们分别为0 2654% (DW), 0 2071% (DW) 和0 2535% (DW)。     

Genetic transformation of gentian using wild-type Agrobacterium rhizogenes

Leaf sections of greenhouse-grown Miscanthus x ogiformis Honda 'Giganteus' plants and leaf sections or shoot apices of in vitro shoot cultures were grown on Murashige and Skoog medium containing various concentrations of benzyladenine (BA) and 2,4-dichlorophenoxyacetic acid. On leaf sections, the callus induction decreased with increasing BA concentration. The percentage of embryogenic callus was increased, the percentage of root-forming callus decreased, and a new shoot-forming callus type was formed by inclusion of BA during callus induction. A higher percentage of shoot-forming callus was formed on shoot apices compared with leaf sections of in vitro-grown shoots when cultured on 0.4 μM BA. The largest number of plants per callus piece was regenerated from shoot-forming callus, but maintenance of the high regeneration capacity proved difficult. This revised version was published online in June 2006 with corrections to the Cover Date.     

发根农杆菌菌株的综合鉴定及活力比较

利用3-酮乳糖产物法、差异酸生成实验和游动性实验鉴定发根农杆菌菌株A4、R1205、R1000、R1601、R1022和15834的菌株类型和活力。结果表明,R1205、R1601、R1000、A4为Ⅱ型农杆菌,其活力从大到小依次是R1000、R1205、A4、R1601。利用PCR方法鉴定表明,A4、R1205、R1000和R1601为发根农杆菌,而R1022和15834未出现阳性结果。黄瓜遗传转化力鉴定结果表明,R1000的遗传转化力最大,达到79.16%,其它菌株依次是R1205、R1601、A4。根据上述三方面综合鉴定,R1000菌株活力最大。     

中药植物黄山药发根基因的遗传转化

以发根农杆菌菌株A4转染已预培养1d的黄山药茎段后,共感染3d,其转化效果最佳;转化毛状根在无生长调节物质的MS培养基上培养可获得丛状芽,并发育成植株。     

Genetic Transformation of Cucumis sativus by Agrobacterium rhizogenes

Hairy roots were obtained in vitro 10 days after inoculation of cucumber ( Cucumis sativus L. ) cotyledon explants with the strains of Agrobacterium rhiwgenes R1000 and R1601. The frequency of the cotyledon explants transformed by R1000 and R1601 was up to 87.5% and 88.9%, respectively. All hairy roots induced by the strains of R1000 and R1601 grew rapidly on solid hormone-free MS medium. The roots incited by A. rhizogenes R1000 could be divided into three phenotypes. The roots of phenotype Ⅰ were similar to the normal ones, but had more numerous lateral roots. Roots of phenotype m were much stouter and shorter, they elongated very slowly and were more highly branched than roots of phenotype Ⅰ . Roots of phenotype Ⅱ were of intermediate in appearance. However, the roots incited by A. rhizogenes R1601 appeared similar to phenotype Ⅰ roots incited by A. rhizogenes R1000. Transformation was confirmed by opine detection.