Physical location of the carotenoid biosynthesis genes Psy and beta-Lcy in Capsicum annuum (Solanaceae) using heterologous probes from Citrus sinensis (Rutaceae)

Carotenoids are responsible for a range of fruit colors in different hot pepper (Capsicum) varieties, from white to deep red. Color traits are genetically determined by three loci, Y, C1, and C2, which are associated with carotenogenic genes. Although such genes have been localized on genetic maps of Capsicum and anchored in Lycopersicon and Solanum, physical mapping in Capsicum has been restricted to only a few clusters of some multiple copy genes. Heterologous probes from single copy genes have been rarely used. Fluorescent in situ hybridization was performed in Capsicum annuum varieties with different fruit colors, using heterologous probes of Psy and beta-Lcy genes obtained from a BAC library of the sweet orange (Citrus sinensis). The probes hybridized in the terminal portion of a chromosome pair, confirming the location of these genes in previous genetic maps. The hybridized segments showed variation in size in both chromosomes.