Using genomics to improve fruit quality

New fruit varieties are needed to satisfy consumers, and the industry is facing new challenges in order to respond to these demands. The emergence of genomic tools is releasing information on polymorphisms that can be utilized to expedite breeding processes in species that are difficult to breed, given the long periods of time required to get new varieties. The present review describes the current stages of the ongoing efforts that are being taken to apply these technologies to obtain varieties with improved fruit quality in species of the family Rosaceae.

A molecular marker approach using intron flanking EST-PCR to map candidate genes in peach (Prunus persica)

In Peach (Prunus persica) several physiological changes, such as woolliness, triggered by chilling injury are involved in major production losses due to cold storage of the fruits during shipping. Additionally, the low level of polymorphisms among peach varieties is an important limitation in the search for new molecular markers that could be associated with economically important traits. Therefore, a functional approach was employed to associate candidate genes with an informative marker in peach. The data was obtained from the results of an in silico analysis of four different cold peach treatments. Thirty two candidate genes were selected that were aligned against Arabidopsis thaliana genomic sequences to design intron-flanking EST-PCR markers. These markers were used to position the candidate genes on the Prunus genetic reference map. In the physiological response to chilling injury, cell wall integrity, carbohydrate metabolism and stress response pathways could be involved, therefore candidate genes associated by Gene Ontology annotation to these pathways were included in the analysis. The designed markers were positioned to the Texas X Earlygold (TxE) genetic reference map through selective mapping methodology (Bin mapping). 72 percent of these new markers showed polymorphism in the TxE Binset population and 31 percent of them were successfully mapped to a genetic position on the Prunus reference map. The bioinformatic methodology used in this work includes a first approach in search for functional molecular markers associated to differentially expressed genes under certain physiological condition which in addition to the Bin mapping approach allows addressing a genetically anchored position to these new markers.