Figure 1.

Phylogenetic tree and gene structure of the PHO1 gene family in plants. The maximum likelihood tree of the land plant PHO1 genes constructed based on the deduced full-length peptide amino acid sequences using the proteins SYG1 in Saccharomyces cerevisiae, SYG-1 in Caenorhabditis elegans, and XPR1in Mus musculus and Homo sapiens as out-groups. Bootstrap values (>50%) for this tree are shown on each branch. The different classes are marked with different colored backgrounds. The genes from the basal land plants are indicated in rose pink; dicot in red, monocots in blue and gymnosperm in green, respectively. The PHO1-like genes in soybean are indicated by arrows. The symbol ‘D’ indicates the detected gene duplication events, and the symbol ‘#’ indicates genes resulted from tandem duplication in their hosts. The black star indicates the 4 important major duplication events during the expansion of PHO1 genes in land plants. Gene structure was predicted based on the sequences from the Phytozome database. Colored boxes represent exons and connecting lines indicate the introns, respectively. The structure of PHO1 genes in the gymnosperm Pinus taeda and Picea glauca are not represented for lack of their genome sequences.