Whole plastid genome-based phylogenomics supports an inner placement of the O. insectifera group rather than a basal position in the rapidly diversifying Ophrys genus (Orchidaceae)

Some lineages of the orchid genus Ophrys exhibit among the highest diversification rates reported so far. As a consequence of a such intense and rapid evolution, the systematics and taxonomy of this genus remain unclear. A hybrid assembly approach based-on long- and short-read genomic data allowed us to outperform classical methods to successfully assemble whole plastid genomes for two new species of Ophrys: O. aymoninii and O. lutea. Along with three other previously Ophrys plastid genome sequences, we then reconstructed the first whole plastome-based molecular phylogeny including representatives of the three mains recognized Ophrys lineages. Our results support the placement of the O. insectifera clade as sister group of non-basal Ophrys rather than a basal position. Our findings corroborate recent results obtained from genomic data (RAD-seq and transcriptomes) but contrast with previous ones. These results therefore confirm that molecular phylogenetic hypotheses based on a limited number of loci (e.g. nrITS, matK, rbcL) may have provided a biased picture of phylogenetic relationships within Ophrys and possibly other plant taxa.

Automated summary

Some lineages of the orchid genus Ophrys exhibit high diversification rates. A hybrid assembly approach using genomic data successfully assembled whole plastid genomes for two new Ophrys species. The research supports the placement of the O. insectifera clade as sister group of non-basal Ophrys.