Abstract

Background: Vernalization is one of the pivotal ways for plants to flower. The twodimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-offlight/ time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were applied to analyze the changes in protein expression profiles in responding to vernalization in leaves of wheat seedling before (0d) and after (30d) of vernalization.

Objective: The main objective of this study was to analyze the vernalization-responsive proteins in winter wheat after vernalization.

Methods: Winter wheat seedling leaf proteins were extracted by phenol extraction coupled with ammonium acetate in methanol. 2-DE was conducted according to procedures described in the manual given by the GE manufacture. The selected protein spots were identified by MALDITOF/ TOF MS. Gene ontology (GO) classification was applied to classify the functions of the differentially expressed proteins. Pathway enrichment analysis identified significantly enriched metabolic pathways or signal transduction pathways relative to the whole proteins background.

Results: The results of 2-DE and MALDI-TOF/TOF MS showed that among the 65 differentially expressed proteins that were successfully identified under vernalization, 30 were up-regulated whereas 35 were down-regulated after vernalization, respectively. These vernalization-responsive proteins were found to play roles in carbohydrate metabolism, protein metabolism, photosynthesis, defense and stress-resistance and may therefore participate in many biological processes in responding to vernalization. The enhanced accumulation of proteins after vernalization, such as thiamine thiazole synthase, late embryogenesis abundant protein, and glutathione-S-transferase, probably play vital roles in the mechanisms underlying vernalization response in wheat.

Conclusion: Our results indicated these vernalization-responsive proteins were found to be involved in protein metabolism, carbohydrate metabolism, photosynthesis, and stress resistance/ defense. The responses of plants to low temperature were very complex, involving in a wide range of cellular pathways for signal transduction, gene regulation, protein modifications, and metabolic regulation. Studying on wheat proteomic profiles in response to vernalization can improve our understanding the molecular mechanisms underlying vernalization in cereals. The results obtained in this study have provided a novel insight into the mechanisms underlying vernalization in cereal crops.

Keywords: Vernalization, wheat, proteomics, 2-DE, MALDI-TOF/TOF MS, protein metabolism.

Graphical Abstract