Complete mitochondrial genome assembly and comparative analysis of Fagopyrum dibotrys (Golden Buckwheat)

Mitochondria and chloroplasts are crucial plant organelles that harbor valuable genetic information. Fagopyrum dibotrys, commonly known as golden buckwheat, is an economically significant plant with diverse pharmacological properties, including antioxidant, antitumor, and anti-inflammatory activities. However, the mitochondrial genome (mt genome) for golden buckwheat has not yet been sequenced, limiting our understanding of its evolutionary characteristics. To address this, we employed a hybrid assembly strategy to assemble the first mt genome sequence of F. dibotrys.

In this study, we sequenced and assembled a mt genome of F. dibotrys (370,284 bp), which exhibited a distinctive multi-branched conformation. The genome comprises 69 genes, including 34 protein-coding genes (PCGs), six rRNAs, 28 tRNAs, and one pseudogene (rpl16). A comprehensive analysis of the PCGs and a comparison with seven closely related species indicated that the mt genomes have undergone adaptive evolution. Notably, five genes (atp4, ccmFn, nad1, nad3, and nad4) exhibited signs of positive selection. We also identified 12 homologous fragments between the chloroplast (cp.) and mt genomes, with a cumulative length of 33,984 bp. Phylogenetic analysis indicated that F. dibotrys was most closely associated with Fallopia aubertii and Fallopia multiflora.

The present study highlights the reliability of mt genes in revealing the phylogenetic relationships of the Polygonaceae family. Moreover, our research provides a crucial foundation for further exploration of the genetic diversity in the genus Fagopyrum and facilitates the utilization of golden buckwheat.