Fig. 1.

Phylogeny analyses of HPT homologous genes in Poales species. A Neighbor joining phylogeny displaying the divergence between HPT (light green) and HGGT (brown) in 22 Poales species. The presence of a divergent HPT lineage (HPT2) was highlighted in light red. B Maximum likelihood phylogeny for the HPT-encoding genes in 22 Poales species. One thousand times bootstrapping and SH-like approximate likelihood ratio test supports were labelled above each branch. The HPT2 lineage were colored in red. C Calibrated species phylogeny for the Poales species. The deduced emergence time of HPT2 was indicated in red dashed line (see Additional file 2 for detailed sequence alignment and tree files)