1,720,998 research outputs found
Agrobacterium tumefaciens-mediated transformation of elite white poplar (Populus alba L.) and regeneration of transgenic plants.
No full textGenetic transformation of Populus nigra by Agrobacterium tumefaciens
No full textTwo clones of Populus nigra L. were tested in vivo and in vitro for their susceptibility to three different Agrobacterium tumefaciens wild-type strains evaluating number and size of resulting calluses. Strain C58 proved to be the most virulent. Various parameters affecting Agrobacterium-mediated transformation of P. nigra clones were further analysed using b-glucuronidase gene transient expression. The clone Jean Pourtet proved to be more susceptible than the clone San Giorgio. A. tumefaciens strain A281 pKIWI105 proved to be the most virulent. The optimal procedure involved dipping of leaf discs into a bacterial suspension (7x108 cells/ml) for 20 min, followed by a 48 h co-cultivation period on semi-solid regeneration medium. Leaf explants were co-cultivated with two disarmed A. tumefaciens strains. Plantlets of San Giorgio were regenerated, tested for b-glucuronidase activity and rooted on selective medium containing kanamycin. Polymerase chain reaction analysis and Southern blot hybridization confirmed the integration of the neomycin phosphotransferase II gene into the poplar genom
Genetic transformation of Populus deltoides and P. x euramericana clones using Agrobacterium tumefaciens
No full textThe susceptibility of different Populus euramericana (Neva, PE68-022 x P. nigra, 71-060 x P. nigra) and P.
deltoides (PE68-022 x P. deltoides) clones to wild-type Agrobacterium tumefaciens strains (A281 and 82.139) was
evaluated in an inoculation experiment, and differences in the frequency of tumor formation (0-48%) were found.
Co-cultivation experiments demonstrated high transformation ability of oncogenic binary A. tumefaciens strains as
compared to disarmed strains. Using oncogenic binary strains, transgenic calluses were obtained from all tested
clones. The presence of acetosyringone did not influence the transformation frequency of the disarmed strains.
Co-inoculation experiments were performed using leaf discs and a bacterial suspension containing both wild-type
and disarmed strains. No positive effects on transformation efficiency were noticed in these conditions either. The
transformation of tumors and kanamycin resistant calluses was confirmed by DNA analysis
Factors affecting Agrobacterium tumefaciens-mediated transformation of several black poplar clones
No full textRegeneration of Populus nigra transgenic plants expressing a Kunitz proteinase inhibitor (KTi3) gene
Full text linkTransgenic poplar (Populus nigra, cv. Jean Pourtet) plants were recovered as a result of Agrobacterium tumefaciensmediated
transformation performed with EHA105 pBIKUN
strain. Plasmid pBIKUN
contains a 650 bp insert
derived from the soybean (Glycine max L.) KTi3, gene, coding for a Kunitz trypsin proteinase inhibitor. A total
of 58 independent transgenic lines were obtained from 200 cocultivated
leaf explants. Southern blot hybridization
analysis demonstrated the presence of KTi3 gene in the poplar genome. Northern blot analysis of different
kanamycinresistant
plantlets confirmed the accumulation of KTi3mRNAand revealed different levels of expression.
The trypsin inhibitory activity was determined in poplar transgenic tissues by means of specific assay. Moreover,
the trypsinlike
digestive proteinases of the polyphagous moth Lymantria dispar (Lepidoptera, Lymantriidae) and
Clostera anastomosis (Lepidoptera, Notodontidae) were detected and inhibited in vitro by Kunitz proteinase inhibitor
from selected transgenic plants. Two insect bioassays were performed on P. nigra transgenic plant lines, using
larvae of the above mentioned insects. In both cases larval mortality and growth as well as pupal weight were not
significantly affected when the insects were fed on transgenic leaves and control leaves, respectively
The Tdp1 (tyrosyl-DNA phosphodiesterase) gene family in Medicago truncatula Gaertn:bioinformatic investigation and expression profiles in response to copper-and PEG-mediated stress
No full textThe Tdp1 gene encoding tyrosyl-DNA phosphodiesterase has been extensively investigated in animal cells, due to the role of this enzyme in the repair of topoisomerase I-DNA covalent lesions. In contrast, information in this regard is totally missing in plants. We report for the first time in plants on the Tdp1 gene family from barrel medic (Medicago truncatula Gaertn.), composed of two members, hereby named MtTdp1a and MtTdp1b. The expression profiles of MtTdp1a and MtTdp1b genes were evaluated in plantlets grown in vitro using copper and polyethylene glycol (PEG 6000) as stress agents. In situ detection of reactive oxygen species (ROS) was carried out by histochemical staining, while the level of oxidative DNA damage, quantified in terms of 7,8-dihydro-8-oxoguanine (8-oxo-dG), increased up to 7.4- and 6.7-fold in response to copper and PEG 6000 treatments, respectively. Quantitative real-time polymerase chain reaction revealed that both Tdp1 genes were significantly up-regulated in response to copper and PEG. The Tdp1 genes were also significantly up-regulated during seed rehydration, an aspect of seed physiology in which DNA repair is a key component. Thus, the Tdp1 genes might be used as novel tools for improving stress tolerance in crops. The expression patterns of the barrel medic top1a and top1b genes, encoding distinct isoforms of DNA topoisomerase I, were also analyzed and discussed to acquire additional information on their specific functions, closely related to that of the Tdp1 gene in animal cells
The Tdp1 (Tyrosyl-DNA phosphodiesterase) gene family in barrel medic (Medicago truncatula Gaertn.): bioinformatic investigation and expression profiles
No full textMolecular cloning of a trypsin inhibitor cDNA from snail medic (Medicago Scutellata) seeds.
No full textIn vitro culture and genetic engineering of Populus spp.: synergy for forest tree improvement
No full textPopulus species and hybrids are intensively cultivated as sources of woody biomass for the forest products industry and for reforestation of lowlands in temperate regions of the world. However, the long generation time of trees, the presence of seasonal dormancy and the prolonged period required for evaluation of mature traits are strong limitations for classical breeding and selection. The development of methods for in vitro culture and genetic engineering has increased the possibility of producing poplar genotypes improved in insect pest resistance, herbicide tolerance, growth rate and wood quality, or reduction in undesirable traits. Poplar has become a model system in forest tree biotechnology due to several useful features: small genome size, short rotation cycle, rapid growth rate and ease of vegetative propagation. The combination of molecular techniques and classical breeding will help create forest trees with positive effects on the environment. However, risks associated with the biotechnological applications (concerning the impact on biodiversity, long-term adaptation, transgene inheritance and stability) should be carefully evaluated and field tests performed with transgenic poplar
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