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1

Present status of Gentiana taxa biotechnology

100%
Mikula A., Rybczynski J. J.
Biotechnologia
|
1999
|
issue 4
76-91
EN
Data on the tissue culture and genetic manipulation of several species of the genus Gentiana in support on the review of literature are presented.
2

Mechanism of Agrobacterium-mediated genetic transformation of plant cell

100%
Nadolska-Orczyk A.
Biotechnologia
|
2001
|
issue 4
100-107
EN
Agrobacterium-mediated genetic transformation is the only known example of horizontal gene transfer from bacteria to eucaryota including plants, fungi and animal cells. The knowledge of the basic mechanism of this process is the key to understand problems concerning methods of plant transformation and transgene expression. The main element of the system is Ti plasmid (tumor-inducing) containing T-DNA (transferred DNA) delimited by 25. nucleotide sequences (left and right borders). Any DNA located on Ti plasmid and flanked by these two borders might be recognised by Agrobacterium as a T-DNA and integrated into plant chromosome. The process is controlled by ten vir operons located on Ti plasmid. The most important products of the vir genes are VirA and VirG controlling the expression of all the other vir genes. VirD1 and VirD2 recognise 25 bp border sequences and take part in endonucleolitic cleavage. Additionally, VirD2 covalently attached to the 5?-end of single stranded (ss) T-DNA targets it into the nucleus of a plant cell. T-strand is coated by VirE2 molecules, each containing two sites of nuclear localisation signals (NLS). Eleven of VirB and VirD4 proteins are required to form a transmembrane channel and transfer T-strand to the plant cell. Some genes of the bacterial chromosome are responsible for bacterial attachment and colonisation of the plant cell.
3

Genetic transformation of Rhododendron sp.

100%
Madej M., Czernicki W., Klein M.
Biotechnologia
|
2006
|
issue 3
36-43
EN
The aim of our study is to review the results of genetic transformation of rhododendrons which has been published in scientific literature or presented during scientific conferences so far. Despite complicated and work-consuming protocol, genetic transformation has great potential to improve future ornamental plants. Rhododendrons of tomorrow could have desired morphological architecture and flower pigmentation, resistance to diseases, pests and harmful environmental conditions. Gene transfer experiments that were carried out so far, proved successful. More and more significant factors are discovered during each investigation. However, that study has to be worked out in order to optimize the efficiency of genetic transformation. Then, we can speculate that traditional rhododendron breeding will be hastened. Breeders will have exclusive plants whose genomes will be transformed in terms of desirable features.
4

Agrobacterium-mediated genetic transformation of cereal crops

88%
Nadolska-Orczyk A., Przetakiewicz A., Orczyk W.
Biotechnologia
|
2000
|
issue 4
93-98
EN
The results published in recent years proved that Agrobacterium based system for genetic transformation was also suitable for cereal crops. Several groups were able to obtain transgenic rice, corn, wheat and barley using hipervirulent strains Agl1 and EHA101 (or EHA105) or 'regular' LBA4404 strain with superbinary vector pTOK233. The first phase of our research was designed to establish transformation susceptibility of two wheat, two barley and one triticale cultivars using three different bacterial systems. Two of those systems were based on hipervirulent strains: Agl1 (pDM805) and EHA101 (pGAH). The third one combined strong virulence of pTOK233 vector and commonly-used LBA 4404 strain. Putative transgenic plants (regenerated and rooted under selective pressure of appropriate factor and further confirmed with GUS or PCR) were obtained for barley (cultivar Scarlett), wheat (Torka and Kontesa) and triticale (Wanad) with Agrobacterium strain Agl1. Kontesa's putative transgenics were also obtained with the strain EHA101. The highest rate of selection of putative transgenics was for Agl1 / phosphinothricine and ranged from 9 to15% for wheat cultivars. The lowest rate for the same strain and selection was 0,5% for barley cv. Scarlett.Inoculation of 700 immature embryos of barley cv. Lot with three bacterial systems (strains, vectors and selection factors) failed to produce putative transformants. Also no putative transgenics of barley Scralett, wheat Torka and triticale Wanad were obtained after transformation with EHA101 and selection on higromycine. Selection with kanamycin and hygromycin + kanamycin after transformation with EHA101 and LBA4404 respectively also failed to give positive results.
5

Transgene expression and gene silencing in cereals

88%
Nadolska-Orczyk A.
Biotechnologia
|
2006
|
issue 4
168-180
EN
Genetic transformation of cereal crops is a powerful research tool for analysis of gene function and varietal improvement. Application of the method is possible when the expression of introduced transgene is on the desired level and stable over several generations. The production of transgenic cereals was mainly performed by microprojectile bombardment. However, some advance was also achieved by application of Agrobacterium-mediated transformation. For rice, which is the cereal model species, this method is routinely used, while for many others, especially polyploids, it has been developed very recently and only in a few laboratories. We still lack the knowledge whether the main features of Agro-mediated transformation (i.e. integration of one or few copies usually not rearranged and well defined transgene cassette) influence the transgene expression in polyploid cereal species. This review discusses known mechanisms possibly involved in transgene silencing, using both transformation methods. Part of the discussion is focused on transgene expression / silencing in relation to large genomes of polyploid cereals. Another application of genetic transformation, based on RNAi technology (RNA interference), is silencing of selected genes. This could be used to study gene function as well as to induce silencing of the native, single or family genes of cereals. Two strategies of silencing are discussed: a strategy of transcriptional gene silencing (TGS) and posttranscriptional gene silencing (PTGS).
6

The significance of plant genetic transformation for modern research

88%
Niemirowicz-Szczytt K.
Biotechnologia
|
2006
|
issue 4
164-167
EN
It has been over ten years now since genetically modified plants, obtained due to genetic transformation, started to be cultivated in many countries all over the world. As a rule, a GM plant is characterized by a new trait developed as a result of gene/genes (T-DNA), derived from another organism. It seems that no in sufficient attention has been paid to the fact that genetic transformation has provided a useful tool for functional plant genomics. The identification of genome sequences of a few species (such as Arabidopsis thaliana, Oryza sativa i Medicago truncatula) and significant progress in genome sequencing of some others, including trees (Populus trichocarpa), lead to an inevitable question about the function of genes. It is the knowledge of the function of DNA sequences that allows for their practical applications. Insertional mutagenesis, based on T-DNA incorporation, meant to cause gene modification resulting in the development of new plant phenotypes. Mutant phenotype ensures isolation and identification of the modified gene. In order to identify the function of a gene which does not bring about phenotype changes, it is necessary to supplement an inserted DNA segment with sequences enabling the monitoring of gene expression. Gene silencing technology is another way to get the information about gene function and to control genes. New techniques are being enriched with improved chemical and physical mutation methods. Further studies and new applications are greatly facilitated by the detection of gene functions with the use of insertional mutagenesis, gene silencing strategy and evaluation of gene expression.
7

Progress and status of doubled haploids of winter oilseed rape (Brassic napus L.) production

75%
Cegielska-Taras T., Bartkowiak-Broda I.
Biotechnologia
|
2006
|
issue 4
107-115
EN
A single microspore cultured in vitro can be reprogrammed from the development of pollen to divisions and production of a bipolar embryo. The final effect of androgenesis in vitro is conversion of each embryo derived from microspore of a heterozygous plant into a doubled haploid plant in such a way that a population of doubled haploids fully represents the genetic variability of the preceding meiosis. DH lines have been already widely used in oilseed rape breeding. Doubled haploids are used by breeders in crossing programs in order to obtain desirable variability in progeny, and also as a part of conventional breeding. Moreover, doubled haploids in conjunction with molecular markers helped to develop the so called 'molecular breeding'.
8

Generation of selectable marker-free transgenic plants

75%
Zuzga S., Burza W., Malepszy S.
|
2003
|
issue 4
32-46
EN
Since the first reports of successful plant transformation appeared, there have been steady improvements of the transformation methods. Nowadays, transgenic plants without the incorporation of selection genes for antibiotic or herbicide resistance would be the only ones acceptable to the public, so elimination of these genes from transgenic crops prior to their field release and commercialization seems inevitable. Several strategies have been developed to generate marker-free transgenic plants, including: positive selection, alternative marker genes, co-transformation, site-specific recombination, transpozon-mediated approaches and intrachromosomal homologous recombination. The efficiency of these methods is various as comparing to the traditional marker assisted selection - higher in case of alternative procedures and lower in others.
9

The effect of transformation with iaglu gene on growth and development of trangenic strawberry in in vitro cultures

75%
Wawrzynczak D., Sowik I., Michalczuk L.
Biotechnologia
|
2004
|
issue 2
46-53
EN
The aim of the presented work was to study the effects of changes of endogenous indole-3-acetic acid (IAA) metabolizm on in vitro shoot proliferation and rhizogenesis of transgenic strawberry shoots carrying maize IAA-glucose synthase gene (iaglu). Four iaglu-transformed strawberry clones and nontransformed 'Kaster' shoots served as a plant material for the study. The analysis of free and conjugated IAA level in leaves of transgenic and control strawberry plants showed that iaglu-containing strawberry clones had significantly higher level of ester conjugated IAA, but the level of free hormone was only slightly decreased or comparable to the control plants. iaglu-transformed clones had significantly higher proliferation rate and formed more roots than the control shoots. One of the iaglu-transformed clones had significantly shorter and other two ? longer roots than the control plantlets.
10

Agrobacterium-mediated transformation of yellow lupin to generate callus tissue producing HBV surface antigen in a long-term culture

75%
Pniewski T., Kapusta J., Plucienniczak A.
Journal of Applied Genetics
|
2006
|
vol. 47
|
issue 4
309-318
EN
The idea of an oral vaccine administered as a portion of plant tissue requires a high level of antigen production. An improved protocol for the induction of transgenic yellow lupin calli or tumours, reaching 44% of transformation rate, is presented here. It has been developed by using the nptII marker gene and the uidA reporter gene as well as various Agrobacterium strains and plant explants. This method of seedling and hypocotyl transformation was applied to raise calli or tumours producing a small surface antigen of Hepatitis B Virus (S-HBsAg). Lupin tissue lines were long-term cultured on selection media maintaining the growth rate and high expression level of the native form of S-HBs, up to 6 mug per g of fresh tissue.
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