According to the NR annotation, 66,000 (38.16 %) unigenes had homologous sequence in the database, of which 14,365 (21.77 %), 4309 (6.53 %), 4173 (6.32 %) unigenes were annotated with homologous genes from Vitis vinifera, Oryza sativa Japonica Group and Prunus persica, respectively (Fig. 2a). The similarity distribution indicated that 54.87 % of the unigenes showed a similarity higher than 60, and 40.04 % unigenes had similarity between 60 and 80 % (Fig. 2b). For the E value distribution, 53.79 % of the top hits had high homology with the E-value <1.0e−50 (Fig. 2c).Fig. 2Characteristics of sequence homology of C. faberi BLASTED against NCBI non-redundant (Nr) database. a E-value distribution of BLAST hits for matched unigene sequences, using an E-value cutoff of 1.0E−5. b Similarity distribution of top BLAST hits for each unigene. c Species distribution of the top BLAST hits