UNRAVELING PEACH FRUIT MEALINESS AND COLD STORAGE BROWNING WITH GENOMIC TOOLS

摘要

Mealiness and cold storage flesh browning are major symptoms of chilling injury (CI) or internal breakdown in peach fruit. Other symptoms are internal bleeding, loss of flavor and development of off flavors. CI occurs in fruit stored at cold temperatures for the purpose of extending shelf life. A dedicated ChillPeach YM EST database and cDNA microarray are being used in combination with the candidate gene approach to identify CI -controlling genes in a peach progeny population (Pop-DG) segregating for CI resistance. A linkage map covering ~95% of the peach genome was constructed for Pop-DG. This map is co-linear with Prunus T X E reference map, allowing cross referencing of markers and traits. Included on both Pop-DG and TxE reference map (through bin-mapping) are 68 novel ChillPeach SSR markers and 69 additional ChillPeach unigenes differentially regulated in normal peach mesocarp tissue versus cold-treated tissue. Several quantitative trait loci (QTL) were detected for CI symptoms in Pop-DG. SomeChillPeach unigenes and candidate genes mapped to the vicinity of QTLs controlling mealiness, flesh browning and bleeding and other CI symptoms. Efforts continue to be made in further mapping and functional characterization of Cl-controlling genes through testing the effects of gibberellin on CI gene expression, extensive microarray analyses, and the validation of CI QTLs obtained from Pop-DG in other peach progeny populations with different genetic backgrounds.