Identification of proteins associated with changes in oligosaccharide metabolism in Lycium barbarum L. fruit by using iTRAQ technology

Abstract

Oligosaccharides are important functional active components of Lycium barbarum L. (LBL, “Goji”) fruits, but their metabolic mechanisms are not yet clear. In this study, we firstly investigated the changes in the content of oligosaccharides in LBL at different stages (S1–S5), and found that it mainly accumulated at S3 and S4. Secondly, the structural characteristics of LBL oligosaccharide (LBO) were studied by GC-MS and FT-IR. Thirdly, using iTRAQ proteomics analysis, we identified 135 differentially expressed proteins associated with oligosaccharide metabolism, which is mainly accomplished through the collaboration of a range of key enzymes. At S1 and S2, oligosaccharide synthesis was achieved mainly through photosynthesis, and changes in anabolism were mainly associated with the expression of sucrose synthase, sucrose phosphate synthase and hexokinase. Oligosaccharide accumulation was achieved through starch and polysaccharide metabolism and cellulose catabolism at S3 and S4, where the enzymes associated with changes in oligosaccharide anabolism included glycosylase, β-fructosidase and glucan endonuclease. This report will provide a theoretical basis for further elucidating the mechanisms of oligosaccharide anabolism during the growth and development of LBL.