Transcription Factor BoMYB28 Is Involved In Regulation Of Sulforaphane Accumulation In Broccoli By Disodium Selenite

Broccoli is rich in sulforaphane,a natural anti-cancer ingredient,and is a green vegetable that is beneficial to human health.Selenium is a micronutrient,and broccoli has enrichment characteristics for it.Previous studies have shown that exogenous selenium treatment can promote the accumulation of sulforaphane in broccoli,but the specific regulatory mechanism is still unclear.Therefore,in this study,different concentrations of sodium selenite(0,10,20,30,40,50 μmol/L)were used to treat broccoli to determine the sulforaphane content,and the optimum concentration of sodium selenite was 40 μmol/L.A series of differentially expressed genes involved in the synthesis of sulforaphane were screened out by transcriptome sequencing analysis at this concentration,and the key transcription factor BoMYB28 was cloned and sequenced by real-time fluorescent quantitative PCR results,and the overexpression and sequencing of BoMYB28 in broccoli were carried out.The interference transformation experiment,and the yeast single-hybrid experiment and the dual luciferase experiment were used to verify the downstream structural genes regulated by it,which provided a basis for exploring the molecular mechanism of how the transcription factor BoMYB28 participates in the regulation of sulforaphane synthesis by sodium selenite.The main findings are as follows:1.The content of sulforaphane in broccoli was 147.88 μg/g FW when treated with 40μmol/L Na2 Se O3,and the expression level of BoMYB28 gene reached the peak at 40 μmol/L,which was 10.40 times that of BoMYB28 gene under CK treatment.2.Transcriptome analysis of broccoli sprouts showed that differentially expressed genes were enriched in the glucosinolate biosynthesis pathway,and the expression levels of BoMYB28 and BoBCAT4 genes were significantly up-regulated under 40 μmol/L Na2 Se O3treatment.3.BoMYB28 was cloned in broccoli,a total of 1056 bp,its protein length is 353 amino acids,its protein size is 39.71 k Da,it is located in the nucleus,and the conserved domain is located in the 1st ~ 134 th amino acid,the protein is conservative and stable,α-Helical strips and random coils are the main structural elements in the secondary structure of the protein.4.Overexpression and vector transformation of BoMYB28 were carried out in broccoli,and the yeast single-hybrid assay and dual-luciferase assay further verified that BoMYB28 directly regulates the downstream gene BoBCAT4.