[Genomic Markers Associated with Cold-Hardiness in Brassica rapa L.]

Brassica rapa L. is a valuable and widespread species, but its cultivation in risk farming areas requires high-quality cold-hardy varieties to be developed. Mechanisms of the cold stress response in plants involve expression of numerous genes, including ribosomal ones, and are related to plant chromosome variability. FISH- and PCR-based methods were used to study intraspecific chromosome variability in the number and localization of 45S and 5S rDNA clusters and also to examine a set of molecular markers associated with cold-hardiness in winter B. rapa cultivars from high-risk farming areas. Several SSR (Na10-CO3 and BrgMS5339-1) and SCAR (BoCCA1-F/BoCCA1-1R1 and BoCCA1-F/BoCCA1-2R1) markers were identified as suitable for diagnosing cold-resistant and cold-susceptible genotypes in B. rapa. Compared with fodder cultivars, oilseed and leaf cultivars were shown to have more molecular markers associated with cold-hardiness and a higher level of polymorphism for the chromosomal distribution of 45S and 5S rDNAs, including chromosome heteromorphism. Thus, the least cold-resistant genotypes were found to display the lowest level of chromosome variability in the distribution of the 45S and 5S rDNA clusters and vice versa. The findings could be useful for the development of new cold-tolerant B. rapa varieties.

[The Use of Specific DNA Markers for the Identification of Alleles of the FAD3 Genes in Rape (Brassica napus L.)].

A search was conducted for the alleles responsible for the quality of food-grade rapeseed oil in a collection of 21 samples of spring and winter oilseed rape of Belarusian and Russian breeding. We also developed A- and C-gene-specific DNA markers to assess the genomic polymorphisms of rape for FAD3 genes and selected plants with a low content of linolenic acid for use in the selection process. The development of a method for identifying FAD3 alleles, which control the level of linolenic acid in rapeseed oil, as well as of the design for new dCAPS markers, enabled the identification of plants homozygous for individual FAD3A and/or FAD3C genes in the F2-generation. These plants are currently involved in the selection process of new varieties with a reduced content of linolenic acid in rapeseed oil.

[Variation in evolutionary unstable regions of the chloroplast genome in plants obtained in anther culture of dihaploid wheat lines].

In dihaploid wheats, two evolutionarily unstable regions of the chloroplast genome were examined. These regions include the following genes, changes in which could be associated with albinism in anther culture: rbcL, encoding the large Rubisco subunit; psaA, encoding p700 apoprotein Ia; petA, encoding cytochrome f; atpB and atpE, encoding respectively beta and epsilon subunits of the CF1 ATPase complex; trnE, encoding glutamine tRNA; and cemA, encoding a cell membrane protein. Using PCR, we have shown that atpB was the gene most often not detected in the lines examined. These results suggest that regeneration of albino plants is accompanied by a deletion of a chloroplast DNA region harboring this gene.