The use of EST-SNP markers to integrate genetic and physical maps for Rosa wichurana.

In previous research a genetic map based on a diploid population Rosa wichurana x R. ‘Yesterday’ was constructed (Moghaddam et al. 2012). As a proof of concept, EST-SNP markers were designed for 3 genes: Phenylalanine ammonia-lyase (PAL), Orcinol O-methyltransferase (OOMT) and Pyrroline-5-carboxylate synthase (P5CS). Polymorphisms were detected using High Resolution Melting (HRM) analysis. The obtained markers were incorporated into the known genetic maps of Rosa (Moghaddam et al. 2012). Furthermore, we physically mapped these 3 genes using Tyramide-FISH for R. wichurana. Optimization of the Tyramide FISH protocol was necessary as R. wichurana is a difficult species for cytogenetics because its tiny roots, hard cell wall, low mitotic index, very small chromosomes (size between 0.86 and 1.52 µm) and high polysaccharide content in the tissues. This multidisciplinary approach allowed us to integrate the genetic and physical maps of chromosomes 1, 4 and 7 of R. wichurana.