Genetic and protein sequence variation of <i>CBF1-4</i> in cold hardy wild grapevine germplasm

Abstract

Grapevine (Vitis vinifera) production is limited by a wide array of abiotic stresses including cold, drought, and salinity stresses. The regulation of stress response genes under these conditions is very complex but a common and essential component of the gene network is the C-Repeat Binding Factor (CBF) genes. Four unique CBF genes have been described in grapevine to date and gene or protein level variation may help explain differences in stress resistance phenotypes in grapevine. This study was conducted to evaluate the level of genetic diversity found at these genes in different wild grapevine species as well as in a panel of cultivated grapevine varieties. Examination of the genetic variation at the four CBF genes in grapevine revealed high sequence variation with many different alleles in wild and cultivated grape. However, predicted protein sequence variation of the different genes revealed a different pattern. Vitis CBF genes 1, 2, and 3, which play roles in the stress response to many different stresses, were seen to have high levels of protein sequence variation. In contrast, VCBF4, which is induced by cold, was seen to have very little variation across all wild and cultivated grapevine samples. This contrasting pattern between different gene family members suggests an essential role of VCBF4 in grapevine as the protein sequence is highly conserved between wild North American grapevine species and cultivated varieties.