GSE69432
Analysis of the transcriptome of  the pulp of a spontaneous late-ripening sweet orange mutant  and its wild type improves our understanding of fruit ripening  in citrus
Fruit ripening is a complex, genetically programmed process that occurs in conjunction with the differentiation of  chloroplasts into chromoplasts and involves changes to the organoleptic properties of the fruit. In this study, an  integrative analysis of the transcriptome and proteome was performed to identify important regulators and pathways  involved in fruit ripening in a spontaneous late-ripening mutant (‘Fengwan’ orange, Citrus sinensis L. Osbeck) and its  wild type (‘Fengjie 72-1’). At the transcript level, 628 genes showed a 2-fold or more expression difference between  the mutant and wild type as detected by an RNA sequencing approach. At the protein level, 130 proteins differed by  1.5-fold or more in their relative abundance, as indicated by iTRAQ (isobaric tags for relative and absolute quantitation)  analysis. A comparison of the transcriptome and proteome data revealed some aspects of the regulation of  metabolism during orange fruit ripening. First, a large number of differential genes were found to belong to the plant  hormone pathways and cell-wall-related metabolism. Secondly, we noted a correlation between ripening-associated  transcripts and sugar metabolites, which suggests the importance of these metabolic pathways during fruit ripening.  Thirdly, a number of genes showed inconsistency between the transcript and protein level, which is indicative of posttranscriptional  events. These results reveal multiple ripening-associated events during citrus ripening and provide  new insights into the molecular mechanisms underlying citrus ripening regulatory networks Overall design: Six samples, the WT and MT fruit pulps harvested at 170, 190, and 210 DAF  were subjected to RNA-seq