Transcriptome dynamics during fruit development of sweet orange (Citrus sinensis)

• To dissect how the genes are dynamically and differentially expressed during fruit development in sweet orange, a comprehensive transcriptomic study was performed in a pleiotropic mutant (MT) and its wild type (WT). • The detection of the fruit transcriptomic changes was conducted at five stages of fruit development by deep sequencing; the obtained millions of reliable tags were mapped on orange unigenes and subjected to cluster analysis and functional categorization. Sugar and organic acid contents were determined based on the prediction of differential biological processes. • The global clustering analysis revealed a total of 14 expression patterns for the genes involved in fruit development of sweet orange. More than 94% of the genes showed differential expression during fruit development. Comparative transcripts profiling between WT and MT revealed that between 410 and 634 genes were significantly differentially expressed at the five stages. Functional categorization indicated that TCA cycle, carotenoid biosynthesis, and pentose phosphate pathway (OPP) were among the most regulated pathways. • This study provided a dynamic-view of the transcriptome changes during fruit ripening in sweet orange; the results highlighted a set of molecular processes involved in the formation of the mutation trait in the orange fruits. Overall design: Investigate the transcriptome changes during five fruit developmental stages of two sweet orange genotypes