Microsatllite markers for cultivar identification in grapevine (Vitis vinifera L.)

Abstract

Identification of grapevine cultivars using methods based on morphological differences between plants may be incorrect due to the influence of environmental factors. For these reasons, alternative methods for cultivar identification, which better illustrate differences at the genotype level, were developed. The diverse techniques for the molecular characterization (isoenzyme, RFLP, RAPD, AFLP, SCAR and SSR markers) developed in the past twenty years have been also applied to the grapevines. Among them, microsatellites show the best value of polymorphism information and are generally very variable. Microsatellites consist of short, tandem repeated DNA motifs and are ubiquitous in most organisms. The polymorphism among individuals is due to changes in the number of repeat units. In the early studies primers for the PCR amplification of the microsatellite loci were designed on the basis of the microsatellite sequences already existing in the Gene Bank databases. Subsequently a strategy was developed towards the construction of a genomic libraries enriched in microsatellites. A large number of microsatellite markers (more than 500) have been developed in grapevines and their extraordinary potential in determining grapevine cultivars and rootstocks was confirmed by numerous studies. The set of six or nine microsatellite markers, which are highly polymorphic and the most appropriate to determine the genetic variability among the European grapevine cultivars, is mainly used in the genotyping analysis. Using a definite set of markers and the integration of reference cultivars in the genotyping analysis allows comparison of genotypes between different research groups, and thus allows solving many dilemmas of synonyms, homonyms and origin or grape varieties.