Phenotypic, biochemical and genomic variability in generations of the rapeseed (Brassica napus L.) mutant lines obtained via chemical mutagenesis.

The phenotypic, biochemical and genetic variability was studied in M2-M5 generations of ethyl methansulfonat (EMS, 0.2%) mutagenized rapeseed lines generated from canola, '00', B. napus cv. Vikros. EMS mutagenesis induced extensive diversity in morphological and agronomic traits among mutant progeny resulted in selection of EMS populations of B. napus- and B. rapa-morphotypes. The seeds of the obtained mutant lines were high-protein, low in oil and stabilized in contents of main fatty acids which make them useful for feed production. Despite the increased level of various meiotic abnormalities revealed in EMS populations, comparative karyotype analysis and FISH-based visualization of 45S and 5S rDNA indicated a high level of karyotypic stability in M2-M5 plants, and therefore, the obtained mutant lines could be useful in further rapeseed improvement. The revealed structural chromosomal reorganizations in karyotypes of several plants of B. rapa-type indicate that rapeseed breeding by chemical mutagenesis can result in cytogenetic instability in the mutant progeny, and therefore, it should include the karyotype examination. Our findings demonstrate that EMS at low concentrations has great potential in rapeseed improvement.

Integration of Physical, Genetic, and Cytogenetic Mapping Data for Cellulose Synthase (CesA) Genes in Flax (Linum usitatissimum L.).

Flax, Linum usitatissimum L., is a valuable multi-purpose plant, and currently, its genome is being extensively investigated. Nevertheless, mapping of genes in flax genome is still remaining a challenging task. The cellulose synthase (CesA) multigene family involving in the process of cellulose synthesis is especially important for metabolism of this fiber crop. For the first time, fluorescent in situ hybridization (FISH)-based chromosomal localization of the CesA conserved fragment (KF011584.1), 5S, and 26S rRNA genes was performed in landrace, oilseed, and fiber varieties of L. usitatissimum. Intraspecific polymorphism in chromosomal distribution of KF011584.1 and 5S DNA loci was revealed, and the generalized chromosome ideogram was constructed. Using BLAST analysis, available data on physical/genetic mapping and also whole-genome sequencing of flax, localization of KF011584.1, 45S, and 5S rRNA sequences on genomic scaffolds, and their anchoring to the genetic map were conducted. The alignment of the results of FISH and BLAST analyses indicated that KF011584.1 fragment revealed on chromosome 3 could be anchored to linkage group (LG) 11. The common LG for 45S and 5S rDNA was not found probably due to the polymorphic localization of 5S rDNA on chromosome 1. Our findings indicate the complexity of integration of physical, genetic, and cytogenetic mapping data for multicopy gene families in plants. Nevertheless, the obtained results can be useful for future progress in constructing of integrated physical/genetic/cytological maps in L. usitatissimum which are essential for flax breeding.

Intraspecific chromosomal and genetic polymorphism in Brassica napus L. detected by cytogenetic and molecular markers.

The application of DNA intercalator 9-aminoacridine allowed us to increase the resolution of chromosome C-banding and DAPI-banding patterns and to investigate chromosomal polymorphism in karyotypes of seven spring and six winter rape varieties. It was shown that the pericentromeric and intercalary C-bands of most of the chromosomes in spring rape were smaller in size and less polymorphic than those of winter rape. More 26S and 5S rDNA sites were found in the winter rape karyotypes than the spring varieties. Separate or colocalized 26S and 5S rDNA sites were revealed on chromosomes 4, 5, 6, 8, 10, 14, 15, 16 and 18. Intervarietal and intravarietal polymorphism of the number and chromosomal localization of rDNA sites were detected. The generalized idiogram of chromosomes of 13 Brassica napus varieties with account of all possibilities of C-banding patterns as well as localization of 26S and 5S rDNA sites were constructed. Polymorphism of the examined molecular and cytogenetic markers as well as the heterozygosis level of FAE1.1 gene controlling erucic acid synthesis in rapeseed was higher in the winter varieties than in the spring ones. The obtained data were in a atisfactory agreement with increased tolerance to environmental stress conditions of winter rape.

Retrotransposon-based molecular markers for analysis of genetic diversity within the Genus Linum.

SSAP method was used to study the genetic diversity of 22 Linum species from sections Linum, Adenolinum, Dasylinum, Stellerolinum, and 46 flax cultivars. All the studied flax varieties were distinguished using SSAP for retrotransposons FL9 and FL11. Thus, the validity of SSAP method was demonstrated for flax marking, identification of accessions in genebank collections, and control during propagation of flax varieties. Polymorphism of Fl1a, Fl1b, and Cassandra insertions were very low in flax varieties, but these retrotransposons were successfully used for the investigation of Linum species. Species clusterization based on SSAP markers was in concordance with their taxonomic division into sections Dasylinum, Stellerolinum, Adenolinum, and Linum. All species of sect. Adenolinum clustered apart from species of sect. Linum. The data confirmed the accuracy of the separation in these sections. Members of section Linum are not as closely related as members of other sections, so taxonomic revision of this section is desirable. L. usitatissimum accessions genetically distant from modern flax cultivars were revealed in our work. These accessions are of utmost interest for flax breeding and introduction of new useful traits into flax cultivars. The chromosome localization of Cassandra retrotransposon in Linum species was determined.