Fig. 4

Phylogenetic tree of all 6 groups of PpNAC transcription factors, their gene structures and protein motifs: a, Phylogenetic tree: The amino acid sequences of all 6 groups were aligned using MUSCLE, and the phylogenetic tree was constructed using the neighbor-joining method through MEGA7 software. Groups are shown by numbers from 1 to 6 with red, green, blue, orange, black and yellow color trees while their subgroups are showed with alphabet letters. b, Gene structure: The exons are represented by red boxes while introns with yellow lines and blue bars indicate the upstream or downstream which was elucidated by using Gene Structure Display Server. The scale bar is represented 1.0 kb (middle). c, Protein motif: schematic diagrams of possible conserved motifs in PpNAC proteins, MEME tool was used to find out the conserved motifs. Conserved motifs (1–10) are indicated by different colored boxes while the non-conserved sequences are showed by the gray lines