Characteristics of natural growing areas for Leucojum aestivum L. in Bulgaria based on chemical composition of plants

The characterization Bulgarian natural growing areas of Leucojum aestivum L. was on the basis of the chemical composition of the plants and some soil characteristics which give an opportunity to choose those conditions suitable for growing and obtaining enlargement of the source of plant material with high galanthamine content. This information should benefit the improvement of natural growing areas for Leucojum aestivum L. as well as for the creation of new industrial plantations.     

Transfer of powdery mildew resistance from Aegilops variabilis into bread wheat

Winter hexaploid wheat (Triticum aestivum L.) was crossed with Aegilops variabilis to transfer resistance to powdery mildew into wheat. Following two backcrosses to wheat and from 5 to 9 generations of selfing, several disomic addition and substitution lines of hexaploid wheat resistant to the mildew pathogen were isolated. A pair of short satellited chromosomes was always observed in the resistant lines. Further evidence utilizing as markers for homoeologous group 1 HMW glutenin subunits and DNA hybridization with probe pGBX 3076 showed that an alien substitution involved this homoeologous group.     

Low variability of flower volatiles of Rosa damascena Mill. plants from rose plantations along the Rose Valley, Bulgaria

The composition of volatile compounds in the rose essential oils obtained from the rose flowers has been known to be affected by a number of factors including the region of rose growing. The variations of the flower volatile composition of Rosa damascena plants growing in 11 different rose plantations along the famous Rose Valley in Bulgaria were studied following GC/MS metabolite profiling. ANOVA statistical test revealed that only 14 of a total of 90 identified compounds were significantly influenced by the geographic location of the sampled rose plantation. The hierarchical clustering analysis based on the subset of these 14 compounds revealed no clear correlation between the levels of rose flower volatiles and geographic location of the studied rose plantations. The results from the study suggest low variability of rose flower volatiles accumulation and elevated plasticity of the common R. damascena genotype industrially cultivated in the Rose Valley.     

Culture selected somaclonal variation in five Triticum aestivum L. genotypes

Somaclones (R₃ and R₄ generations) regenerated from five winter wheat (Triticum aestivum L.) genotypes were evaluated for variation in agronomic and morphological characters. Immature embryos were used as initial explant material. Comparisons for plant height, top internode length, spike length, number of seeds per spike and 100 seed weight were made between the somaclones and their parents. Some morphological variations of stem and spike characteristics were registered which demonstrate that plant height and spike length can be changed by using immature embryo culture. The results obtained may be considered a biotechnological contribution to wheat plant improvement. This revised version was published online in August 2006 with corrections to the Cover Date.     

Agronomic performance and molecular assessment of tissue culture-derived barley lines

In order to assess the genetic variability among regenerants. field trials were conducted with 64 barley lines derived from tissue culture (TCD lines) of four Bulgarian barley varieties. The results indicate that the agronomic performance was altered by tissue culture regeneration and the frequency of variation was cultivar dependent. Seven TCD lines showing desirable agronomic characters were selected in the SC1₆ progeny. Molecular markers (protein, restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) have used applied to determine the variability induced by tissue culture. Polymorphism was detected in sequences coding for C-hordeins in line 70 derived from cv.‘Jubiley’Two lines from cv.‘Ruen’exhibited polymorphic bands after hybridization with a mitochondrial DNA probe. RAPD assays have been carried out using 20 different l0-mer primers. Heritable polymorphisms in several TCD lines have been observed.     

Influence of chemical composition of soils on the galanthamine content in Levcojum aestivum

The elemental composition of seven soils of the main geographical regions in Bulgaria for the growth of Leucojum aestivum L. was determined. It was found that a relationship exists between the galanthamine content of the plant and the chemical composition of the soil. These results indicate that galanthamine bio‐ synthesis could be controlled by the soil fertility level.     

A simple, flexible and efficient PCR-fusion/Gateway cloning procedure for gene fusion, site-directed mutagenesis, short sequence insertion and domain deletions and swaps

Background  

The progress and completion of various plant genome sequencing projects has paved the way for diverse functional genomic studies that involve cloning, modification and subsequent expression of target genes. This requires flexible and efficient procedures for generating binary vectors containing: gene fusions, variants from site-directed mutagenesis, addition of protein tags together with domain swaps and deletions. Furthermore, efficient cloning procedures, ideally high throughput, are essential for pyramiding of multiple gene constructs.     

Genetic diversity among elite Bulgarian barley varieties evaluated by RFLP and RAPD markers

Genetic variation among five elite winter barley cultivars (H. vulgare L.) currently grown in Bulgaria was assessed at the molecular level using restriction fragment length polymorphism (RFLP) and randomly amplified polymorphic DNA (RAPD) markers. The present study sampled RFLPs in four well characterized multigene families in barley: the seed storage protein loci; the 18S, 5.8S and 26S ribosomal DNA loci; the loci coding for 5S ribosomal RNA and the loci coding subunit α of ATP-A complex in the mitochondrial genome. RFLPs were detected in three out of five investigated chromosomal loci in the barley cultivars studied. RAPD assay using arbitrary 10-base primers was applied to generate amplified length polymorphic markers in barley. Overall a total of 15 polymorphic phenotypes were found among the studied barley cultivars by using 11 out of 25 tested primers. All RAPDs were considered as dominant genetic markers except for two, where PCR and Southern blot analysis indicated the presence of codominant amplification products. Five RAPD polymorphisms in F₁ and F₂ progenies of the cross between Alpha and Obzor were inherited in Mendelian fashion. The determined values for the genetic variation proved a high genetic similarity among the tested cultivars. Genetic similarity (GS) calculated from RFLP and RAPD data ranged from 0.888 to 0.997 with a mean GS – 0.933. This revised version was published online in July 2006 with corrections to the Cover Date.     

Preparation and characterization of fibers of waste and fresh polyethylene terephtalate and mixtures of them

Textile fibers were obtained from secondary polyethylene terephtalate (PET) and its mixtures with primary PET at initial orientation of 18000–33000 %, rate of additional orientation drawing 3.5–6.5 times and temperature of thermal fixation 363–413 K. The fibers’ tensile strength was found to decrease and elongation at break to increase with the decrease of their linear density under the conditions of fibers formation. For the fibers based on polymer mixtures, the presence of oxidized fragments in the secondary PET limited the compatibility of the two polymers which resulted in deteriorated tensile properties. The linear density (4–16 dtex), tensile strength (30–50 cN/tex) and elongation at break (20–60 %) of the PET fibers obtained were close to these for the industrially produced polymer fibers. The values of the average diameter of the fibers formed and oriented under laboratory conditions allows classifying them between the fine and the coarse textile fibers which makes them suitable for the textile industry.