Fruit quality and differentially expressed genes of winter-harvested pineapple in response to elevated temperature over a short postharvest period

Abstract

The aim of this work was to investigate the influences of elevated postharvest temperature (EPT) for 1d and 2d on the physicochemical quality of pineapple fruit and the differentially expressed genes (DEGs) underlying this process by RNA-seq. The results suggested that EPT increased the L*, a*, b* of pineapple fruit skin. EPT decreased the L* and increased the a* and b* of pineapple pulp. EPT increased the total soluble solid (TSS), sucrose content and TSS/titratable acidity (TA) ratio and decreased the TA. EPT decreased the firmness of pineapple fruit. At 1d, EPT improved the production of aromatic alkenes. At 2d, EPT improved the production of aromatic esters and decreased the alkenes. A differential gene expression analysis suggested that a total of 6725 and 5845 DEGs were identified by comparing EPT and control at 1d and 2d, respectively. A number of DEGs were screened for their involvement in the EPT process effects on pineapple fruit, including those associated with coloration, sugar/acid metabolism, texture softening and aroma biosynthesis. A subset of these DEGs was validated by qPCR, which was consistent with the corresponding Reads Per Kilo bases per Million reads (RPKM values) from RNA-seq. The findings of this study contribute to our understanding of how EPT regulates the quality of pineapple fruit over different durations and the molecular mechanisms underlying this process.