Functional Genomics as a Tool to Understand Cracking Tolerance in Sweet Cherry (Prunus avium)

The Chilean fruit industry has positioned itself as a key market for the country’s development. To lead this market at the international level, it is necessary that Chile produce fruits and arrive to those markets with them in a very good condition/quality. Sweet cherries have become a fruit with a high value for the exporters and the growers. One of the problems associated with loss of production is cracking of sweet cherry fruit. Towards this end, it is essential to understand the molecular mechanisms that are involved in this disorder as well as identify genes and markers linked to this problem. In order to achieve this goal two approaches are under way. A biochemical approach was carried out to determine the role of alkenes in cracking using five different varieties of sweet cherry. After removal of cuticular wax, fruit cracking was significantly increased. Nuclear magnetic resonance analysis (¹H- and ¹³C-NMR), revealed that fruits of different sweet cherry varieties contain primarily n-alkane with 29 carbons and no iso-alkane. Gas chromatography–mass spectrometry (GC-MS) enabled identification and quantification of n-alkanes. Varieties with significantly higher concentrations of nonacosane (Kordia, Regina and Lapins) were more tolerant to cracking compared to varieties with lower amounts (Bing and Rainier).

On the other hand, we used 454 Roche technology (454 GS-FL and 454 GS-FLX) to sequence the transcriptome of mature fruit from three sweet cherry varieties (Bing, Lapin and Rainier). Then, using CLC Genomics Workbench de novo assembly, we obtained a reference transcriptome of 20,349 contigs over 200 bp with a mean length of 919 bp. Illumina sequencing was performed for Bing variety under cracking water stress conditions. Several genes that might be involved in this disorder were identified. We have initiated a plum linkage map to validate and position the genes identified in sweet cherry.

This work is supported by CONICYT, FONDECYT/Regular Nº1120261