Proteomic Analysis Of Chinese Cabbage Seeds In Response To Vernalization

Vernalization plays a crucial role in the progression from vegetative to reproductive growth as an important floral induction way in mostly winter or biennial plants.As typical seed-vernalization crop,Chinese cabbage is sensltive to low temperature during seed germination stage that promotes flowering early.So,vernalization is commonly used to accelerate the breeding process of Chinese cabbage.However,the regulation mechanism of vernalization in Chinese cabbage seeds is not clear.In our experiment,Chinese cabbage seeds were treated with low temperature and studied protein expression profile changes using iTRAQ to reveal the mechanism of Chinese cabbage seeds in response to vernalization.The main contents and results are described as follow:1.The seeds were vernalizaed with different days and the bolting time showed that the plants would bolt earlier with the increasing days of exposing to low temperature.Thus,treated for 25 days can effectively complete vernalization in Chinese cabbage seeds.2.Compared proteome analysis of germinated seeds(Ger)?vernalizaed seeds(Ver)and normal seeds(Nor,equal in length to Ver)using iTRAQ technology,a total of 4197 proteins were identified.Among these identified proteins,641?604?644 proteins showed differentially expressed in Nor-VS-Ver?Ger-VS-Ver?Ger-VS-Nor,respectively.3.GO enrichment and KEGG enrichment analysis showed that differentially expressed proteins in Nor-VS-Ver were acted as the enzymes or molecular chaperones that plays a central role in different biological processes such as carbohydrate metabolism,protein metabolism,biosynthesis of secondary metabolites and response to stimulus.4.Venn diagram analysis of the differentially expressed proteins identified between Ger-VS-Ver and Ger-VS-Nor.329 specially expressed proteins were identified and functional analysis indicate that these proteins also involved in the metabolism of carbohydrates,amino acids,lipids and other substances,accompanied by energy metabolism and signal transduction.5.Western blot were performed to detect the expression level of two GDSL lipase proteins and qRT-PCR were performed to detect the expression level of twelve differentially expressed proteins which related to stress response,growth and antioxidation,demonstrated the reliability of proteomic data at protein level and transcriptional level.6.The correlation analysis of proteome and transcriptome for the same samples showed that only a few genes were correlated and the correlation between mRNA and protein levels are modest,indicating that there exist the transcriptional regulation of differentially expressed proteins during vernalization process in Chinese cabbage seeds.