Phylogenetic relationship, gene structure and motif compositions of Populus HD-ZIP genes.

A. The phylogenetic tree was constructed using full-length protein sequences by the maximum likelihood method with 100 bootstrap replicates. The percentage bootstrap scores higher than 50% are indicated on the nodes. The four major phylogenetic subfamilies designated as I to IV are marked with different color backgrounds. B. Exon/intron structures of HD-ZIP genes from Populus. Exons and introns are represented by green boxes and black lines, respectively. The sizes of exons and introns are proportional to their sequence lengths. C. Schematic representation of the conserved motifs in the HD-ZIP proteins from Populus elucidated by MEME. Each motif is represented by a number in the colored box. The details of individual motif are provided in Table S4.