The phylogeny and divergence time of Ophiocordyceps sinensis and its host insects based on elongation factor 1 alpha

Ophiocordyceps sinensis Berk. is a fungal parasite that parasitizes the larvae of Hepialidae and is endemic to the Qinghai-Tibet Plateau (QTP). The phylogeny and divergence time of O. sinensis and its host insects were analyzed for 137 individuals from 48 O. sinensis populations based on the elongation factor 1 alpha (EF-1α) gene. Lower nucleotide variation, with only 7 and 16 EF-1α haplotypes, was detected in O. sinensis and its host insects, respectively. The isolated and broad distribution patterns coexisted in both O. sinensis and its host insects on the QTP. The divergence time estimates show that O. sinensis and its host insects originated later than 14.33 million years (Myr) and earlier than 23.60 Myr in the Miocene period, and the major differentiation occurred later than 4 Myr. Their origin and differentiation match well with the second and third uplifts of the QTP, respectively. The host insects from the O. sinensis populations distributed around Qinghai Lake are inferred as an ancient and relict species that has survived various geological events of the QTP. It is suitable to estimate the divergence times of both O. sinensis and its host insects from the same individuals using one gene: EF-1α. Our findings of the origin, phylogeny, and evolution of the endemic species also support the epoch of geological events on the QTP.