Development and mapping of peach candidate genes involved in fruit quality and their transferability and potential use in other Rosaceae species

The goal of the present study was to identify candidate genes (CGs) involved in fruit quality in peach that can be transferred to other Rosaceae species. Two cDNA libraries from fruit of the “Fantasia” peach cultivar, constructed at two stages of development, were used to generate a set of expressed sequence tag sequences. A total of 1,730 peach unigenes were obtained after clustering. Sequences and corresponding annotations were stored in a relational database and are available through a web interface. Fifty-nine CGs involved in fruit growth and development or fruit quality at maturity, focusing on sweetness, acidity, and phenolic compound content, were selected according to their annotation. Fifty-five primer pairs, designed from peach CG sequences and giving PCR products in peach, were tested in strawberry and 36 gave amplified products. Eight CGs were mapped in peach, 14 in strawberry, four in both species and confirmed the pattern of synteny already proposed using comparative mapping. In peach, the CGs are located in three linkage groups (3, 5, 7), and in strawberry they are distributed in all seven Fragaria linkage groups. Colocalization between some of these CGs and quantitative trait loci for fruit quality traits were identified and are awaiting confirmation in further analyses.
This research was partially funded by the European ISAFRUIT Integrated Project. The ISAFRUIT project is funded by the European Commission under the Thematic Priority 5—Food Quality and Safety of the 6th Framework Programme of RTD (contract number FP6-FOOD-CT-2006-016279). We thank Dr. Christophe Rothan for his involvement in the construction of the cDNA libraries and Christel Renaud for her participation in the preparation of EST clones for sequencing. The strawberry research was supported in part with funds from the Spanish Ministry of Science and Innovation project INIA (RTA2007-00063-00-00) and Euroberry COST Action 863. JB was supported by a fellowship from AGAUR.