Molecular Characterization of 'Plavac Mali' and 'Sangiovese' Berry Color Mutants

Due to vegetative propagation, grapevine cultivars are supposed to be genetically identical offspring of a parent seedling. However, over time, spontaneous mutations occur within the populations of cultivars resulting in vines with new traits. This phenomenon has been utilized in selection to establish subpopulations with new agronomic values, usually called clones. Clones of a cultivar often have unique and superior traits. Mutations in grape berry skin are known and found in several cultivars (e.g., 'Pinot' family). Color of the grape berry skin is dependent on the presence or absence of anthocyanin. Anthocyanin biosynthesis is mostly controlled by a cluster of Myb-type genes. 'Plavac Mali' is a major Croatian red cultivar and 'Sangiovese' is the most widely planted red cultivar in Italy. Color mutants of these cultivars have been found, including a pink mutant of 'Plavac Mali', also called 'Plavac Mali sivi', and several bud sports of 'Sangiovese'. In this study, layer specific molecular characterization has been performed. Leaf and root DNA samples have been used to test if the mutations are chimeric. Genome regions along chromosome 2 containing Myb genes were analyzed using previously known and newly developed SSR markers. Applied markers enabled differentiation of mutants and wild types in both cultivars, but in spite of very similar phenotypes, genetic backgrounds were different.