Functional annotation and classification of unigenes
To investigate information on gene functions more comprehensively, a total of 57812 unigenes were annotated using six databases including Nr, Pfam, Swiss-prot, COG, GO, and KEGG. The results of annotation of the unigenes are as follows: 18388 (31.81%) unigenes were annotated in Nr; 14039 (24.28%) in Pfam; 11986 (20.73%) in Swiss-prot; 14479 (25.04%) in COG; 14129 (24.44%) in GO, and 9176 (15.87%) in KEGG (Figure 2 and Table S3).