The complete plastome sequence of Gnetum ula (Gnetales: Gnetaceae).

This study reports the complete plastome sequence of Gnetum ula, a gymnosperm species of Gnetaceae (Gnetophyta). The plastome is 113 249 bp long. It has a quadripartite structure containing a pair of large inverted repeat regions of 19 772 bp each, a large single-copy region of 64 914 bp, and a small single-copy region of 8791 bp. One hundred sixteen genes were predicted in the plastome, including 68 protein-coding genes, eight ribosomal RNA genes, and 40 transfer RNA genes. The gene density is 1.024 (genes/kb). Similar to other known Gnetum plastomes, the G.ula plastome has lost 20 protein-coding genes commonly present in other seed plant plastomes. Our phylogenetic analyses indicate that the four sampled Gnetum species are monophyletic and that G. ula is close to the two other lianas rather than the only small tree species, G. gnemon. Our phylogenetic trees also indicate that gnetophytes have the fastest evolutionary rates among gymnosperms.