Fig. 4

GO analysis of DP proteins (a) and quantitative RT-PCR analysis of the mRNA abundance of the corresponding DP protein genes (b). Standardized residue was employed for the statistical analysis of GO enrichment, where standardized residue [=(Observed-expected)/√expected], which follows asymptotically a normal distribution [86]. An absolute SR value larger than 2.33 indicates statistical significance at P < 0.01. Based on the distribution of each GO category in genome, an expected number of DP proteins in each GO category could be calculated out. Observed is the number actually occurred in each GO category * indicates P < 0.05; ** indicates P < 0.01