The seed transcriptome of <i>Rafflesia</i> reveals horizontal gene transfer and convergent evolution: Implications for conserving the world's largest flower

Rafflesia is of great interest as one the only two plants known to have completely lost its chloroplast genome. a holoparasite and an endophyte that lives inside tissues host, tropical grape vine (Tetrastigma), emerging bloom—with largest flower any plant. Here, we report first seed transcriptome compare it with those other deepen our understanding extraordinary life history. We assembled from RNA extracted seeds Philippine endemic speciosa compared this plants, including Arabidopsis, parasitic Striga Cuscuta, mycoheterotrophic orchid Anoectochilus. Genetic metabolic pathways in were generally similar plant species. However, there some notable exceptions. found evidence horizontal transfer gene potentially involved circumventing host defenses. Moreover, identified possible convergence among because Rafflesia, Striga, Cuscuta shared important similarities. unable find genes mycorrhizal symbiosis, suggesting mycoheterotrophy unlikely play role parasitism. To date, ex situ propagation by has been mostly unsuccessful. Our research bold step forward fundamentals biology will inform continued seed-banking efforts concerning recalcitrant discuss findings broader context conservation genus peril.