Molecular characterization of the virulence gene virA of the Agrobacterium tumefaciens octopine Ti plasmid

1987 ◽  
Vol 9 (6) ◽  
pp. 635-645 ◽  
Author(s):  
Leo S. Melchers ◽  
Dave V. Thompson ◽  
Ken B. Idler ◽  
Saskia T. C. Neuteboom ◽  
Ruud A. de Maagd ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Molecular Characterization ◽  
Virulence Gene ◽  
Ti Plasmid

Molecular characterization of the virulence gene virA of the Agrobacterium tumefaciens octopine Ti plasmid

1988 ◽  
Vol 11 (2) ◽  
pp. 227-237 ◽  
Author(s):  
Leo S. Melchers ◽  
Dave V. Thompson ◽  
Ken B. Idler ◽  
Saskia T. C. Neuteboom ◽  
Ruud A. de Maagd ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Molecular Characterization ◽  
Virulence Gene ◽  
Ti Plasmid

scholarly journals Correction: characterization of the virB operon from Agrobacterium tumefaciens Ti plasmid.

1990 ◽  
Vol 265 (8) ◽  
pp. 4768
Author(s):  
J E Ward ◽  
D E Akiyoshi ◽  
D Regier ◽  
A Datta ◽  
M P Gordon ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Ti Plasmid ◽  
Virb Operon

Characterization of the virA virulence gene of the nopaline plasmid, pTiC58, of Agrobacterium tumefaciens

1989 ◽  
Vol 3 (9) ◽  
pp. 1237-1246 ◽  
Author(s):  
P. Morel ◽  
B. S. Powell ◽  
P. M. Rogowsky ◽  
C. I. Kado
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Virulence Gene

scholarly journals Molecular characterization of the virC genes of the Ti plasmid.

1987 ◽  
Vol 169 (6) ◽  
pp. 2336-2344 ◽  
Author(s):  
T J Close ◽  
R C Tait ◽  
H C Rempel ◽  
T Hirooka ◽  
L Kim ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Ti Plasmid

scholarly journals Integrated approach for the molecular characterization of edited plants obtained via Agrobacterium tumefaciens-mediated gene transfer

2021 ◽  
Author(s):  
Lorenza Dalla Costa ◽  
Daniela Vinciguerra ◽  
Lisa Giacomelli ◽  
Umberto Salvagnin ◽  
Stefano Piazza ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Gene Transfer ◽  
Molecular Characterization ◽  
Good Practice ◽  
Integrated Approach ◽  
Digital Pcr ◽  
Plant Genome ◽  
Practical Case ◽  
Knock Out

AbstractAgrobacterium tumefaciens-mediated gene transfer—actually the most used method to engineer plants—may lead to integration of multiple copies of T-DNA in the plant genome, as well as to chimeric tissues composed of modified cells and wild type cells. A molecular characterization of the transformed lines is thus a good practice to select the best ones for further investigation. Nowadays, several quantitative and semi-quantitative techniques are available to estimate the copy number (CN) of the T-DNA in genetically modified plants. In this study, we compared three methods based on (1) real-time polymerase chain reaction (qPCR), (2) droplet digital PCR (ddPCR), and (3) next generation sequencing (NGS), to carry out a molecular characterization of grapevine edited lines. These lines contain a knock-out mutation, obtained via CRISPR/Cas9 technology, in genes involved in plant susceptibility to two important mildew diseases of grapevine. According to our results, qPCR and ddPCR outputs are largely in agreement in terms of accuracy, especially for low CN values, while ddPCR resulted more precise than qPCR. With regard to the NGS analysis, the CNs detected with this method were often not consistent with those calculated by qPCR and ddPCR, and NGS was not able to discriminate the integration points in three out of ten lines. Nevertheless, the NGS method can positively identify T-DNA truncations or the presence of tandem/inverted repeats, providing distinct and relevant information about the transgene integration asset. Moreover, the expression analysis of Cas9 and single guide RNA (sgRNA), and the sequencing of the target site added new information to be related to CN data. This work, by reporting a practical case-study on grapevine edited lines, explores pros and cons of the most advanced diagnostic techniques available for the precocious selection of the proper transgenic material. The results may be of interest both to scientists developing new transgenic lines, and to laboratories in charge of GMO control.

scholarly journals Molecular Characterization of Salmonella from Human and Animal Origins in Uganda

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Atek Atwiine Kagirita ◽  
Andrew Baguma ◽  
Tonny Jimmy Owalla ◽  
Joel Bazira ◽  
Samuel Majalija
Keyword(s):  
Multiplex Pcr ◽  
Molecular Characterization ◽  
Molecular Diversity ◽  
One Health ◽  
Virulence Genes ◽  
Classification Scheme ◽  
Virulence Gene ◽  
Clinical Presentations ◽  
Animal Isolates

Sporadic Salmonella outbreaks with varying clinical presentations have been on the rise in various parts of Uganda. The sources of outbreaks and factors underlying the different clinical manifestation are curtailed by paucity of information on Salmonella genotypes and the associated virulence genes. This study reports molecular diversity of Salmonella enterica and their genetic virulence profiles among human and animal isolates. Characterization was done using Kauffman-White classification scheme and virulence genes analysis using multiplex PCR. Overall, 52% of the isolates belonged to serogroup D, 16% to serogroup E, 15% to poly F, H-S, and 12% to serogroup B. Serogroups A, C1, and C2 each consisted of only one isolate representing 5%. Virulence genes located on SPI-1 [spaN and sipB] and on SPI-2 [spiA] in addition to pagC and msgA were equally distributed in isolates obtained from all sources. Plasmid encoded virulence gene spvB was found in <5% of isolates from both human epidemic and animal origins whereas it occurred in 80% of clinical isolates. This study reveals that serogroup D is the predominant Salmonella serogroup in circulation and it is widely shared among animals and humans and calls for joint and coordinated surveillance for one health implementation in Uganda.

scholarly journals The MexE/MexF/AmeC Efflux Pump of Agrobacterium tumefaciens and Its Role in Ti Plasmid Virulence Gene Expression

2020 ◽  
Vol 202 (8) ◽  
Author(s):  
Andrew N. Binns ◽  
Jinlei Zhao
Keyword(s):  
Gene Expression ◽  
Agrobacterium Tumefaciens ◽  
Efflux Pump ◽  
Bacterial Pathogen ◽  
Virulence Gene ◽  
Ti Plasmid ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Extracellular Milieu ◽  
Phenol Derivatives

ABSTRACT Expression of the tumor-inducing (Ti) plasmid virulence genes of Agrobacterium tumefaciens is required for the transfer of DNA from the bacterium into plant cells, ultimately resulting in the initiation of plant tumors. The vir genes are induced as a result of exposure to certain phenol derivatives, monosaccharides, and low pH in the extracellular milieu. The soil, as well as wound sites on a plant—the usual site of the virulence activity of this bacterium—can contain these signals, but vir gene expression in the soil would be a wasteful utilization of energy. This suggests that mechanisms may exist to ensure that vir gene expression occurs only at the higher concentrations of inducers typically found at a plant wound site. In a search for transposon-mediated mutations that affect sensitivity for the virulence gene-inducing activity of the phenol, 3,5-dimethoxy-4-hydroxyacetophenone (acetosyringone [AS]), an RND-type efflux pump homologous to the MexE/MexF/OprN pump of Pseudomonas aeruginosa was identified. Phenotypes of mutants carrying an insertion or deletion of pump components included hypersensitivity to the vir-inducing effects of AS, hypervirulence in the tobacco leaf explant virulence assay, and hypersensitivity to the toxic effects of chloramphenicol. Furthermore, the methoxy substituents on the phenol ring of AS appear to be critical for recognition as a pump substrate. These results support the hypothesis that the regulation of virulence gene expression is integrated with cellular activities that elevate the level of plant-derived inducers required for induction so that this occurs preferentially, if not exclusively, in a plant environment. IMPORTANCE Expression of genes controlling the virulence activities of a bacterial pathogen is expected to occur preferentially at host sites vulnerable to that pathogen. Host-derived molecules that induce such activities in the plant pathogen Agrobacterium tumefaciens are found in the soil, as well as in the plant. Here, we tested the hypothesis that mechanisms exist to suppress the sensitivity of Agrobacterium species to a virulence gene-inducing molecule by selecting for mutant bacteria that are hypersensitive to its inducing activity. The mutant genes identified encode an efflux pump whose proposed activity increases the concentration of the inducer necessary for vir gene expression; this pump is also involved in antibiotic resistance, demonstrating a relationship between cellular defense activities and the control of virulence in Agrobacterium.

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