Figure 2. Phylogenetic relationships, gene structures and motif compositions of Populus trihelix genes.

(a) An unrooted phylogenetic tree generated with the MEGA5.0 program using the full-length amino acid sequences with 1000 bootstrap replicates. The five subfamilies are marked with different colors. (b) Exon/intron structures of Populus trihelix genes. Exons and introns of each subfamily are represented by colored boxes and black lines, respectively. (c) Schematic representation of the conserved motifs in Populus trihelix proteins by MEME. Each colored box represents a motif, and black lines represent non-conserved sequences.