Nopaline

About: Nopaline is a research topic. Over the lifetime, 433 publications have been published within this topic receiving 25955 citations. The topic is also known as: (S)-N-(4-((Aminoiminomethyl)amino)-1-carboxybutyl)-D-glutamic acid & N(2)-(D-1,3-dicarboxypropyl)-L-arginine.

New Agrobacterium helper plasmids for gene transfer to plants

Abstract: We describe the construction of new helper Ti plasmids forAgrobacterium-mediated plant transformation. These plasmids are derived from three differentAgrobacterium tumefaciens Ti plasmids, the octopine plasmid pTiB6, the nopaline plasmid pTiC58, and the L,L-succinamopine plasmid pTiBo542. The T-DNA regions of these plasmids were deleted using site-directed mutagenesis to yield replicons carrying thevir genes that will complement binary vectorsin trans. Data are included that demonstrate strain utility. The advantages ofAgrobacterium strains harbouring these ‘disamed’ Ti plasmids for plant transformation viaAgrobacterium are discussed.

The hypervirulence of Agrobacterium tumefaciens A281 is encoded in a region of pTiBo542 outside of T-DNA.

Abstract: We used a binary-vector strategy to study the hypervirulence of Agrobacterium tumefaciens A281, an L,L-succinamopine strain. Strain A281 is hypervirulent on several solanaceous plants. We constructed plasmids (pCS65 and pCS277) carrying either the transferred DNA (T-DNA) or the remainder of the tumor-inducing (Ti) plasmid (pEHA101) from this strain and tested each of these constructs in trans with complementary regions from heterologous Ti plasmids. Hypervirulence on tobacco could be reconstructed in a bipartite strain with the L,L-succinamopine T-DNA and the vir region on separate plasmids. pEHA101 was able to complement octopine T-DNA to hypervirulence on tobacco and tomato plants. Nopaline T-DNA was complemented better on tomato plants by pEHA101 than it was by its own nopaline vir region, but not to hypervirulence. L,L-Succinamopine T-DNA could not be complemented to hypervirulence on tobacco and tomato plants with either heterologous vir region. From these results we suggest that the hypervirulence of strain A281 is due to non-T-DNA sequences on the Ti plasmid.

Large plasmid in Agrobacterium tumefaciens essential for crown gall-inducing ability

Abstract: THE gram-negative bacterium Agrobacterium tumefaciens induces crown gall tumours in many, mostly dicotyledonous, plants. Zaenen et al.1 demonstrated the presence of one or more large plasmids in a number of crown gall-inducing Agrobacterium strains belonging to seven different Agrobacterium groups. They were not able to find such plasmids in eight non-pathogenic Agrobacterium strains belonging to four of the same groups2,3. They therefore formulated the hypothesis that the genetic information for the tumour-inducing principle4 in crown gall-inducing Agrobacterium strains is carried by one or several large plasmids.

Plasmid required for virulence of Agrobacterium tumefaciens.

Abstract: The irreversible loss of crown gall-inducing ability of Agrobacterium tumefaciens strain C-58 during growth at 37 C is shown to be due to loss of a large plasmid (1.2 X 10-8 daltons). The gene responsible for this high rate of plasmid loss at elevated temperatures seems to be located on the plasmid. In addition, another spontaneous avirulent variant, A. tumefaciens strain IIBNV6 is shown to lack the virulence plasmid which its virulent sibling strain, IIBV7, possesses. Deoxyribonucleic acid reassociation measurements prove that the plasmid is eliminated, not integrated into the chromosome, in both of the avirulent derivatives. Transfer of virulence from donor strain C-58 to avirulent recipient strain A136 results from the transfer of a plasmid, which appears identical to the donor plasmid by deoxyribonucleic acid reassociation measurements. The transfer of virulence in another cross, K27 X A136, was also shown to result from the transfer of a large plasmid. These findings establish unequivocally that the large plasmid determines virulence. Two additional genetic determinants have been located on the virulence plasmid of A. tumefaciens strain C-58: the ability to utilize nopaline and sensitivity to a bacteriocin produced by strain 84. The latter trait can be exploited for selection of avirulent plasmid-free derivatives of strain C-58. The trait of nopaline utilization appears to be on the virulence plasmid also in strains IIBV7 and K27.

A chimaeric antibiotic resistance gene as a selectable marker for plant cell transformation

Abstract: The T-DNA region of Agrobacterium tumefaciens tumour-inducing plasmids of the nopaline type1 contains a gene coding for the enzyme nopaline synthase. This gene is expressed constitutively in host plant cells to which it is transferred during tumour induction2. We have exploited the regulatory elements of this gene to construct a chimaeric gene that confers antibiotic resistance on transformed plant cells. The chimaeric gene encodes the expected chimaeric transcripts in plant cells, and confers on transformed cells the ability to grow in the presence of normally lethal levels of the antibiotic G418 (ref. 3). Experiments using in vitro transformation techniques on single plant cells indicate that this antibiotic resistance can be used as a selectable marker, and can therefore be used in selecting cells transformed by T-DNA vectors that have had the genes for hormone autotrophy deleted4. Plant cells transformed by such ‘disarmed’ T-DNA vectors can be regenerated into entire plants, whose sexual progeny contain unaltered copies of the inciting T-DNA5. The availability of this dominant selectable marker should allow a wider range of experiments to be under taken using different host plants.