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1

Characterization of a cucumber (Cucumis sativus L.) somaclonal variant with paternal inheritance

100%
Malepszy S., Burza W., Smiech M.
Journal of Applied Genetics
|
1996
|
vol. 37
|
issue 1
65-78
EN
Regeneration of cucumber from leaf explants resulted in a new species phenotype designated mosaic (msc).It is characterizes by two types of spots on teh leaves (zucchini-like and chlorophyllous) and has many altered morphological and physiological properties including slower growth, smaller organs, poorly germinating or empty seeds and smaller number of flowers per node.In msc plants the shape of the first leaf is always altered, and in about 76% of the flowers the crown is reduced and distorted to a varying degree.Chloroplasts of the zucchini-like sectors are filled with large starch grains, and some of the embryos die at various stages of development.The msc phenotype is ransmitted uniparentally only by the male plants and no segregation is observed in the F2 and subsequent generations.Possible mechanisms responsible for msc phenotype and its transmission are discussed.
2

Characteristics of somaclonal variation in rye (Secale cereale L.)

100%
Rakoczy-Trojanowska M.
Biotechnologia
|
2002
|
issue 2
175-183
EN
As it was shown in numerous works concerning various plant species tissue culture derived plants may serve as potential variability resources for breeding. This subject was also investigated in rye. However, the number of publications is relatively low. A somaclonal variation in rye was investigated on different levels as molecular one, cytological or morphological. Based on these searches, several general conclusions can be drawn: (1) the frequency of somaclonal changes in rye is high, which can be connected with the presence of genome region, especially susceptible for tissue culture conditions, (2) the range and spectrum of somaclonal changes depend on donor plant genotype, (3) the majority of somaclonal changes has an negative character, e.g. reduction of plant viability, fertility or yield quality influence negatively plant quality, (4) some somaclonal changes can be useful for rye breeding.
3

ISSR evaluation of genetic stability of Polish tulip cultivars propagated in vitro

100%
Podwyszynska M., Kuras A., Korbin M.
Biotechnologia
|
2010
|
issue 2
105-114
EN
The aim of the study was an early detection of somaclonal variation (SV) which could occur within the micropropagated plant material. Shoot cultures of the Polish cultivars were used. Five cultivars derived from breeder A and four from breeder B. They were propagated in vitro for one or two years. The molecular markers (inter-simple sequence repeat, ISSR) were utilized for analysis of putative DNA polymorphism between standard plants (propagated traditionally) belonging to tested cultivars and somaclonal variants derived from them. Within the nine studied genotypes, for five of them, the ISSR analysis performed with ten primers did not reveal polymorphism between standard and micropropagated plants. The analysis of the other four cultivars, all derived from breeder B, showed that some of the plants, micropropagated either for one or two years, differed slightly from standard. Basing on ISSR data, the UPGMA dendrogram showing genetic similarity of the analysed plants was generated and clusters grouping cultivars, their standards and micropropagated plants were noted.
4

Unintended consequences of plant transformation: a molecular insight

100%
Filipecki M., Malepszy S.
Journal of Applied Genetics
|
2006
|
vol. 47
|
issue 4
277-286
EN
Plant genomes are dynamic structures having both the system to maintain and accurately reproduce the information encoded therein and the ability to accept more or less random changes, which is one of the foundations of evolution. Crop improvement and various uncontrolled stress factors can induce unintended genetic and epigenetic variations. In this review it is attempted to summarize factors causing such changes and the molecular nature of these variations in transgenic plants. Unintended effects in transgenic plants can be divided into three main groups: first, pleiotropic effects of integrated DNA on the host plant genome; second, the influence of the integration site and transgene architecture on transgene expression level and stability; and third, the effect of various stresses related to tissue handling, regeneration and clonal propagation. Many of these factors are recently being redefined due to new researches, which apply modern highly sensitive analytical techniques and sequenced model organisms. The ability to inspect large portions of genomes clearly shows that tissue culture contributes to a vast majority of observed genetic and epigenetic changes. Nevertheless, monitoring of thousands transcripts, proteins and metabolites reveals that unintended variation most often falls in the range of natural differences between landraces or varieties. We expect that an increasing amount of evidence on many important crop species will support these observations in the nearest future.
5

Somaclonal variation at the nucleotide sequence level in rice (Oryza sativa L.) as revealed by RAPD and ISSR markers, and by pairwise sequence analysis

100%
Ngezahayo F., Dong Y., Liu B.
Journal of Applied Genetics
|
2007
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vol. 48
|
issue 4
329-336
EN
The nature of somaclonal variation at the nucleotide sequence level was studied in rice cv. Nipponbare. First, we investigated genomic variations by using 2 molecular marker systems: RAPD (random amplified polymorphic DNA) and ISSR (inter-simple sequence repeat). This was followed by sequencing of selected bands that represented genomic variations, and pairwise sequence analysis taking advantage of the whole genome sequence of rice. In addition, transpositional activity of the active MITE, mPing, was analysed by locus-specific PCR amplifications. The 2-year-old calli and their regenerated plants, analysed with 24 RAPD and 20 ISSR primers, showed moderate levels of genomic variation (20.83% and 17.04%, respectively). To test whether DNA methylation plays a role in somaclonal variation, the calli were treated with 5-azacytidine, a chemical agent that reduces cytosine methylation by blocking the activity of DNA methyltransferase. Though dwarfism occurred in regenerants from treated calli (a hallmark of the drug treatment), there was only a slight increase in the frequency of somaclonal variation detected in the treated calli and their regenerated plants relative to untreated controls. The transposon mPing also remained immobile in both treated and untreated calli. Nevertheless, dendrograms constructed according to the Jaccard coefficient calculated by UPGMA of the ISSR bands revealed that the 5-azacytidine-treated and untreated somaclones were grouped into 2 distinct clusters, suggesting a possible indirect effect of the treatment on the genomic changes, depending on the marker used. Sequence analysis indicated a low level of variation (0.31%), with single-base-pair substitutions predominating.
6

Tissue-culture-responsive and autotetraploidy-responsive changes in metabolic profiles of cucumber (Cucumis sativus L.)

100%
Filipecki M., Yin Z., Wisniewska A., Smiech M., Malinowski R., Malepszy S.
Journal of Applied Genetics
|
2006
|
vol. 47
|
issue 1
17-21
EN
Somaclonal variation commonly occurs during in vitro plant regeneration and may introduce unintended changes in numerous plant characters. In order to assess the range of tissue-culture-responsive changes on the biochemical level, the metabolic profiles of diploid and tetraploid cucumber R1 plants regenerated from leaf-derived callus were determined. Gas chromatography and mass spectrometry were used for monitoring of 48 metabolites and many significant changes were found in metabolic profiles of these plants as compared to a seed-derived control. Most of the changes were common to diploids and tetraploids and were effects of tissue culture. However, tetraploids showed quantitative changes in 14 metabolites, as compared to regenerated diploids. These changes include increases in serine, glucose-6P, fructose-6P, oleic acid and shikimic acid levels. Basing on this study we conclude that the variation in metabolic profiles does not correlate directly with the range of genome changes in tetraploids.
7

Somaclonal variation in winter wheat (Triticum aestivum L.): frequency, occurrence and inheritance

100%
Cheng X. Y., Gao M. W., Liang Z. Q., Liu G. Z.
Journal of Applied Genetics
|
1998
|
vol. 39
|
issue 1
59-72
EN
Plants were regenerated from immature embryo cultures of 35 winter wheat genotypes. General responses of regenerated plants were investigated and a total of 7142 R2 spike lines from 1593 Rl plants were assessed in the field for somaclonal variants in 1985/86, 1986/87 and 1987/88. Selected variants were studied for their possible genetic inheritance. From regenerated plantlets, 81% survived and 63% produced fertile plants. Forms with reduced plant height, length of spike and other morphological abnormalities were found in this progeny. Populations of Rl plants were highly variable due mainly to the physiological disturbances resulting from the in vitro process. Overall somaclonal variation frequencies were 14.2% per plant basis and 5.3% per R2 spike basis. The variants were similar in the three different R2 generations with predominant variants being negative in plant height, maturity, awns, spike type and plant type. Both uniform R2 variant families and spike lines were found in addition to the segregating variants which constituted the majority. On average, in a variant family or line, 18% and 14% of their component lines and plants were variants, respectively. Inheritability was demonstrated for the uniform variant families and spike lines as well as segregated variants. Of those 134 selections, about 70% were classified as inheritable. Both recessive and dominant gene mutations at one, two or three loci were evident in some variants as suggested by the segregating data.
8

Different level of point mutation and chromosomal changes among regenerants in tissue culture of Arabidopsis thaliana (L.) Heynh.

100%
Nabialkowska D., Szarejko I., Siwinska D.
Biotechnologia
|
2004
|
issue 2
79-85
EN
Using the regeneration method described by Feldman and Marks (1986), the level of somaclonal variation (frequency of gene mutations and chromosomal changes) was determined in A. thaliana regenerants from root and shoot explants. The explants were regenerated via indirect organogenesis with callus stage. The level of embryo lethal mutations and changes in chromosome number were estimated in R2 generative progeny of regenerants, and confirmed in R3 generation. The frequency of R1 plants carrying gene mutations was similar for all types of explants and on average it reached 8.3%, however only 47% of R1 plants showed the presence of the same embryo mutation in R2 and R3 generation. The frequency of embryo-lethal mutants, among 25 571 embryos tested, was 1.7%, while 0.08% embryos carried chlorophyll mutations. The plants with increased chromosome number were observed in the progeny of 32.2 % R1 regenerants, i.e. with eight times higher frequency than regenerants carrying gene mutations. All polyploid plants were obtained from shoot explants, while regenerants from roots carried normal diploid number of chromosomes. The observed changes in chromosome number were discussed in relation to the different content of DNA in root and shoot cells of A. thaliana.
9

Induction of genetic variation in vitro

100%
Skucinska B.
Biotechnologia
|
2001
|
issue 3
145-151
EN
The effectiveness of traditional methods for inducing genetic variation has greatly increased with the introduction of various techniques in vitro. The new methods of obtaining generative and somatic hybrids in vitro have resulted in a greater recombinant variation, exceeding the levels delimited hitherto by mating barriers. The potential for producing mutants has expanded due to the use of mutant somatic cells (brought in with the explant) as well as to the application of mutagens to individual cells and protoplasts, the haploid ones in particular. Two specific types of variation, i.e. somaclonal and gametoclonal variation, have proved to arise under the influence of various factors in tissue culture. However, the full application of these two types is inhibited to some extent by the constrains on the regeneration ability of plants in culture, on the possibility to select variants in vitro, and on the continuity of the resulting changes. Cultures in vitro also make it possible to introduce directional genetic changes through the application of molecular techniques.
10

Application of in vitro culture techniques to barley (Hordeum vulgare L.) improvement

88%
Ullrich S. E., Kleinhofs A., Hou L., Jones B. L.
Journal of Applied Genetics
|
1998
|
vol. 39
|
issue 1
49-58
EN
Several aspects of in vitro culture have potential for cereal improvement. This paper focuses on evaluation of somaclonal variation (SV) from immature embryo callus culture, and doubled haploid (DH) production via anther culture in barley. Genetically stable SV was observed for several seedling morphological traits such as albino, yellow, light green and lethal. SV occurred at approximately half the frequency of azide-induced mutagenesis. The potential for widespread application of anther culture-mediated DH production in barley breeding and genetic studies was increased through culture procedure improvements and understanding the inheritance of anther culture response. Methodology improvements included substitution of inexpensive gelrite for expensive ficoll or agarose, ability to grow anther donor plants under field as well as growth chamber conditions and flexibility in cold pretreatment/storage of anther donor spikes for 4-6 weeks prior to anther plating. From diallel analysis, inheritance of anther culture response was complex with additive and dominance effects for embryoid formation, total plant regeneration and green plant regeneration and reciprocal effects (maternal) for green plant regeneration. High x low responder crosses generated F1's that were intermediate in response and low x low crosses sometimes produced F1 heterosis for green plant regeneration. Therefore, some recalcitrant types appear to be usable in anther culture DH production systems within a breeding program.
11

In vitro culture and biotechnology ? fulfilled expectations?

88%
Malepszy S., Burza W.
Biotechnologia
|
2010
|
issue 2
10-17
EN
The methods for in vitro culture of plant cells, tissues and organs had focused much attention in the beginning of the last century, which resulted in setting up the first commercial laboratories over 60 years ago. These laboratories concentrated their activity on clonal propagation and their economical importance has been permanently growing. However, some of the applications of in vitro methods are still not realistic, whereas introduction of other is not satisfactory. Plant breeding is an example where application of tissue culture techniques is below expectations. There are several reasons for such situation. Two of them are of biological nature (genotypic effect, somaclonal variation), and the third reason results from the development of other molecular methods providing alternative solutions. We suggest that the main limitations in more effective usage of in vitro methods should be minimized by the development of efficient plant stem cells' culture procedures.
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