Proteomic changes during seed different development period by iTRAQ quantitative proteomics in pomegranate（Punica granatum L.）

Abstract:【Objective】This study aims to investigate the molecular mechanism underlying pomegranateseed hardness by comparing the protein expression profiles between soft- and hard-seeded varieties in 60and 120 days after flowering (DAF).【Methods】The protein expression profiles between soft- and hardseededpomegranate varieties were analysed by using the isobaric mass tags for relative and absolute quan⁃titation technology (iTRAQ).【Results】In total, 1 940 protein groups were identified from pomegranate, ofwhich 1 889 proteins were quantified. When setting quantification ratio of >1.5 as up-regulated thresholdand<0.67 as down- regulated threshold, 154 differentially expressed proteins were obtained in eachgroup, 75 up-regulated, 60 down-regulated, and 19 co-expression. Intensive bioinformatics analysis wasthen carried out to annotate those quantifiable targets, including protein annotation, functional classification, functional enrichment, functional enrichment-based cluster analysis, etc.【Conclusion】In all, duringthe development of seed, several proteins involved in the secondary cell wall biosynthesis and degrada⁃tion, such as F5H, XYL, Elongation factor 1-beta, Elongation factor 1-delta and Profilin, set the foundation for further research on molecular mechanisms related to pomegranate seed hardness.