| The hybridization sugar beet was obtained from the interspecific hybridization between the diploid cultivated species sugar beet(Beta vulgaris L.)and the tetraploid wild species sugar beet(Beta corollifiora Zoss.).The heterologous triploid sugar beet was produced by the backcross between the hybridization sugar beet and the cultivated sugar beet.The heterologous triploid continuingly backcross to produce the monosomic additional line containing one extra chromosome from the wild species,which has some excellent traits such as disease resistance,stress resistance,salt tolerance and apomixis.Protein phosphorylation is one of the most basic and important covalent modifications.Phosphorylation is a dynamic and reversible process.Reversible phosphorylated proteins are closely related to the regulation of kinases and phosphatases in cells.They participate in many cellular processes,such as transmembrane signaling,protein conformation changes,which directly regulate the activity of proteins and lead to changes in subcellular localization.Plant roots serve as the main place for sensing signals and transporting nutrients.Under salt stress conditions,understanding the signaling and metabolic mechanisms of salt stress in roots is essential for improving plant salt tolerance.Therefore,it is important to study the differentially expressed phosphorylated proteins in the root of M14 line in response to salt stress.The differentially expressed phosphorylated proteins of sugar beet M14 leaves under salt stress were analyzed.Therefore,the phosphorylated proteomics analysis of the sugar beet M14 root under different Na Cl(0 m M,200 m M,400 m M.)treatments was performed by label free technique.The root enzymes activities(SOD,POD,CAT)of sugar beet M14 root were determined at different time points after salt stress.Treatments at 200 m M and 400 m M Na Cl for 10 min and 20 min were determined as the time points and treatment coonditions for phosphorylated proteomics analysis.The total protein extraction,enzymatic hydrolysis,desalting and phosphorylation enrichment of the sugar beet M14 root were carried out.The samples has been identified by mass spectrometry.The total 1599 differentially expressed phosphorylated peptides between the control group and the salt treatment group were screened out by Proteome Discover 2.2 software.755 differentially expressed phosphorylated peptides were identified at 200 m M Na Cl compared to 0 m M Na Cl treatment.844 differentially expressed phosphorylated peptides were identified at 400 m M Na Cl compared to 0 m M Na Cl treatment.There are 145 shared proteins corresponding to the differentially expressed phosphorylated peptides between 200 m M and 400 m M Na Cl treatment.In order to further study the changes of phosphorylated proteins in root response to salt stress,the identified phosphorylated proteins were annotated and classified by GO classification and related references.According to the biological functions,the phosphorylated proteins were divided into nine categories,including cell structure(6.1%),metabolism(25.5%),folding and degradation(3.7%),protein synthesis(9.4%),signal transduction associated protein kinase(13.8%),stress and defense(8.3%),transcription(17.1%),Transshipment(13.9%),unknown(2.3%).The results showed that the proportion of phosphorylated proteins in metabolism,transcription,transport and signal transduction associated protein kinase was large.It can be seen that the phosphorylated proteins of transcription,metabolism,transport and signal transduction associated kinase proteins in roots more effects on plant growth,development and metabolism pathways under salt stress.15 significant change proteins in phosphorylation level,which were involved in plant transcription,metabolism,signal transduction and transportation pathways were selected according to the protein funtions and KEGG pathways.Real time-PCR was used to validate the transcriptional level of 15 genes encoding differentially phosphorylated proteins in sugar beet M14 root.This study laid a solid foundation for comprehensively revealing the salt tolerance mechanism of sugar beet M14 root. |
