PLASTID DNA SEQUENCE DIVERSITY IN WILD GRAPEVINE SAMPLES (VITIS VINIFERA SSP. SYLVESTRIS) FROM THE CAUCASUS REGION: COMPLETE PLASTID GENOME SEQUENCES OF THREE GEORGIAN SAMPLES

Abstract

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 this research was to investigate plastid DNA sequence diversity in a geographically diverse set of South Caucasian Vitis vinifera ssp. sylvestris samples. DNA sequence diversity was investigated at three plastid regions (the trnH-psbA intergenic spacer, accD-psaI intergenic spacer and the rpl16 intron) in a group of 40 wild grape (Vitis vinifera ssp. 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 were 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 subjected to 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. vinifera ssp. vinifera), except for one sample where two 4-bp long inversions were detected. These observations highlight both unique and high levels of genetic variation in wild grapes (V. vinifera ssp. sylvestris) from the South Caucasus region and underlines their importance in the process of grape domestication in general.