Chloroplast Genome Variation and Phylogenetic Relationships of Autochthonous Varieties of from the Don Valley.

The autochthonous grape varieties of the Don Valley, situated in southern Russia, constitute a distinctive element of regional cultural heritage. These varieties have been adapted over centuries to the region's specific local climatic and soil conditions. For the most part, these varieties are not imported from other countries. They are closely related to varieties found in Crimea and the North Caucasus. In this study, we obtained the first complete, unfragmented sequences of the chloroplast genomes of eight autochthonous varieties from the Don Valley and one from Crimea. We also performed a comparative analysis of their genomic features. The size of chloroplast genome sequences varied from 160,925 to 160,991 bp, depending on the cultivar, with a uniform GC ratio of 37.38%. Each genome consists of four subregions: a single copy region (LSC) ranging from 89,158 to 89,336 bp, a small single copy region (SSC) ranging from 19,070 to 19,073 bp, and a pair of inverted repeat regions (IRa and IRb) in the range of 26,292 to 26,353 bp. The chloroplast genomes of the studied varieties contained 130 genes, including 85 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. The sequence divergence analysis has enabled the identification of four highly variable regions, which may be utilized as potential markers for phylogenetic analysis. The analysis revealed the presence of 58 to 61 SSRs and multiple long repeated sequences in the chloroplast genomes of these varieties. The phylogenetic analyses of the sequences obtained and complete chloroplast genomes available from public databases indicated that the majority of autochthonous varieties do not have a direct origin from any European variety.