Genome-wide analysis of AP2/ERF transcription factors family inBrassica napus

The AP2/ERF transcription factor family plays an important role in different biological processes such as growth, development and response to abiotic and biotic stresses in plants. The genome-wide analysis identified 531 AP2/ERF genes inBrassica napus(oilseed rape or canola) that ranged from 333 to 6440 bp in genomic and 273-2493 bp in coding DNA sequence length. We classified BnAP2/ERF proteins into five subfamilies including AP2 (58 genes), ERF (250 genes), DREB/CBF (194 genes), RAV (26 genes), and Soloist (3 genes). Furthermore, AP2/ERF proteins were subdivided into 15 groups according to the AP2/ERF classification inArabidopsis. The number of exons inBnAP2/ERFgenes was from one to eleven and most of these genes in the same subfamily had the same exon-intron pattern. The results also indicated that the composition of conserved motifs in most proteins in each group was similar. The intron-exon patterns and the composition of conserved motifs validated the BnAP2/ERF transcription factors phylogenetic classification. Based on the results of genome distribution,BnAP2/ERFgenes were located unevenly on the 19B. napuschromosomes. The results indicated that gene duplication may play an important role in genome expansion ofB. napus. Furthermore, genome evolution ofB. napususing orthologous and paralogous identification was studied. We found 278, 380 and 366 orthologous gene pairs betweenB. napuswithA. thaliana,B. rapaandB. oleracea, respectively. The results of this study will be useful in investigation of functional role and molecular mechanisms ofBnAP2/ERFtranscription factors genes in response to different stresses.