%0 Journal Article %A Seydina Diop %A Andrew D. W. Geering %A Françoise Alfama-Depauw %A Mikaël Loaec %A Pierre-Yves Teycheney %A Florian Maumus %T Tracheophyte genomes keep track of the deep evolution of the Caulimoviridae %D 2017 %R 10.1101/158972 %J bioRxiv %P 158972 %X Endogenous viral elements (EVEs) are viral sequences that are integrated in the nuclear genomes of their hosts and are signatures of viral infections that may have occurred millions of years ago. The study of EVEs, coined paleovirology, provides important insights into virus evolution. The Caulimoviridae is the most common group of EVEs in plants, although their presence has often been overlooked in plant genome studies due to misidentification by automatic annotation programs. We have refined methods for the identification of caulimovirid EVEs and interrogated the genomes of a broad diversity of plant taxa, from algae to advanced flowering plants. Evidence is provided that almost every vascular plant (tracheophyte), including the most primitive taxa (clubmosses, ferns and gymnosperms) contains caulimovirid EVEs, many of which represent previously unrecognized evolutionary branches. In angiosperms, EVEs from at least two and as many as five different caulimovirid genera were frequently detected and florendoviruses were the most widely distributed, followed by petuviruses. For reasons that are unknown, citrus and castor bean contained particularly high densities of caulimovirid EVEs, about 10 times higher than the average across all seed plants. From the analysis of the distribution of different caulimovirid genera within different plant species, we propose a working evolutionary scenario in which this family of viruses has emerged during the Silurian era (approx. 420 million years ago) when land plants first emerged. %U https://www.biorxiv.org/content/biorxiv/early/2017/07/04/158972.full.pdf