Plastid DNA Sequence Diversity in Wild Grapevine Samples (Vitis vinifera subsp. sylvestris) from the Caucasus Region: Complete Plastid Genome Sequences of Georgian Samples

The South Caucasus region is widely believed to be the area in which grape domestication began, and the study of genetic diversity of wild grape samples in this region is viewed as a key to understanding grape domestication in general. The primary goal of thisresearch  was to investigate plastid DNA sequence diversity in a geographically diverse set of South Caucasian Vitisviniferasubsp. sylvestrissamples. DNA sequence diversity was investigated at three plastid regions (the trnH-psbAintergenic spacer, accD- psaIintergenic spacer and the rpl16 intron) in a group of 40 wild grape (Vitisviniferasubsp. sylvestris) samples from the South Caucasus and at the same time complete plastid DNA sequence analysis of  three Georgian wild grape samples were performed. Four plastid haplotypes are evident in the 40 samples, and are designated by their character states at each of the 4 polymorphic positions: AAAT , ATTT , GTAC and ATAT.Each haplotype has specific geographic distribution in the Caucasus region. Three Georgian wild grape samples from haplotype AAAT were subject of complete chloroplast DNA Illumina sequencing. Sequence data analyses revealed complete identities between the sequences of AAAT haplotype wild grapes and the reference – Georgian cultivar Rkatsiteli(V. viniferasubsp. vinifera), except only one sample where two 4 bplong inversions were detected. These observations highlight both unique and high levels of genetic variation in wild grape (V. viniferasubsp.sylvestris) from the South Caucasus region and underlines their importance in the process of grape domestication in general.