The complete annotated plastome sequences of six genera in the tropical woody Polygonaceae.

backgroundThe Polygonaceae is a family well-known for its weeds, and edible plants, Fagopyrum (buckwheat) and Rheum (rhubarb), which are primarily herbaceous and temperate in distribution. Yet, the family also contains a number of lineages that are principally distributed in the tropics and subtropics. Notably, these lineages are woody, unlike their temperate relatives. To date, full-genome sequencing has focused on the temperate and herbaceous taxa. In an effort to increase breadth of genetic knowledge of the Polygonaceae, we here present six fully assembled and annotated chloroplast genomes from six of the tropical, woody genera: Coccoloba rugosa (a narrow and endangered Puerto Rican endemic), Gymnopodium floribundum, Neomillspaughia emarginata, Podopterus mexicanus, Ruprechtia coriacea, and Triplaris cumingiana.

resultsThese assemblies represent the first publicly-available assembled and annotated plastomes for the genera Podopterus, Gymnopodium, and Neomillspaughia, and the first assembled and annotated plastomes for the species Coccoloba rugosa, Ruprechtia coriacea, and Triplaris cumingiana. We found the assembled chloroplast genomes to be above the median size of Polygonaceae plastomes, but otherwise exhibit features typical of the family. The features of greatest sequence variation are found among the ndh genes and in the small single copy (SSC) region of the plastome. The inverted repeats show high GC content and little sequence variation across genera. When placed in a phylogenetic context, our sequences were resolved within the Eriogonoideae.

conclusionsThese six plastomes from among the tropical woody Polygonaceae appear typical within the family. The plastome assembly of Ruprechtia coriacea presented here calls into question the sequence identity of a previously published plastome assembly of R. albida.