A comparative proteomic study of white and black glutinous rice leaves
Background Black glutinous rice contains remarkable levels of anthocyanins, which possess anti-oxidative properties and thus have health benefits. The accumulation of anthocyanins in grains of thirty black glutinous rice varieties was measured, and the results revealed that the accumulated anthocyanin content ranged from 0.262 to 2.539 mg/g. Black glutinous rice Br no. 19 was selected, and its leaf protein expression profile was compared with that of white glutinous rice RD 6 using 2D-PAGE, and the protein spots were then directly analyzed after proteolysis by LC-MS/MS. Results The proteins from the leaves of the two rice varieties were separated using 2D-PAGE and silver stained, and the spots were analyzed using Image Master 2D Platinum version 5 software. The results showed that the protein profiles of these two rice cultivars were different, with at least six protein spots that were detected only in Br no. 19. In addition, seven protein spots accumulated at higher levels in Br no. 19 than in RD 6. Conclusion The protein spot S1 (AP005098.4) is homologous to the Rc protein. Our results suggest that some of the proteins enriched in Br no. 19 may be involved in anthocyanin synthesis in the black glutinous rice.