Analysis of genetic diversity and signature of selection in the genome of grapevine clones of Apulian and Campanian varieties

The genetic diversity of the cultivated grapevine (Vitis vinifera) is made by an enormous population of varieties. Although sexual reproduction led to an outstanding level of inter-varietal variability, spontaneous somatic mutations have further contributed to shape the kaleidoscope of grape diversity. For centuries, growers have collected and propagated these different selections and labeled them as “clones”, that represent an untapped genetic resource useful for designing effective conservation strategies and improving traits of economic importance in grapevine. This work aims to analyze population structure and adaptation signatures in the genome of 130 clones belonging to six grape varieties from Campania and Apulia, genotyped using a reduced representation sequencing approach. The intra- and inter-clonal genetic diversity was analyzed using metrics such as nucleotide diversity and genetic dissimilarity as well as population structure and fixation index (Fst). Divergent signatures between Campanian and Apulian accessions and among germplasms were detected, some of which were associated with traits important for grape breeding. Overall, this work emphasizes the need to recover the untapped genetic variability that characterizes minor grape varieties and the requirement to preserve and use grapevine genetic resources more efficiently in breeding programs.