Identification of Differentially Expressed Proteins in Abortive Seeds of Lumnitzera littorea Based on iTRAQ

【Objective】The study was conducted to explore the molecular mechanism of the abortive seeds of endangered mangrove Lumnitzera littorea.【Method】The expression difference in proteome of different fertility seeds of L. littorea was analyzed by iTRAQ quantitative proteomics technology. Enzymolysis was conducted for two qualified proteomes, which were labelled by iTRAQ and then detected by HPLC and MS. Protein identification was carried out by using Mascot software. Differentially expressed proteins were found by iTRAQ. Then, GO function annotation, KEGG metabolic pathway and protein interaction analysis were performed. Furthermore, eight candidate genes were validated by quantitative realtime PCR.【Results】In the two proteomes, 2 380 proteins were identified, and 448 proteins were differentially expressed in the abortive seeds of L. littorea. Among the differentially expressed proteins, 238 of them were up-regulated proteins and 210 were down-regulated ones. 1.86% of the differentially expressed proteins were closely related to the biological processes of reproduction. GO analysis indicated that most of the up-regulated proteins in the abortive seeds were mainly involved into endoplasmic reticulum protein processing, RNA transport, RNA degradation, SNARE interactions in vesicular transport and mRNA regulation. The UGGT proteins, HSP proteins and the vesicle-associated membrane proteins probably play important regulation roles in the development of abortive seeds. These results reflect the possible biochemical and physiological processes of germination of the abortion L. littorea seeds.【Conclusion】Some transcription factors involved in seed germination and plant growth expressed differently, which may be the direct or indirect reasons for seed abortion. The study results provided scientific support for the research on the mechanism of endangered L. littorea and the conservation of such germplasm resources.