title: Plant genomes enclose footprints of past infections by giant virus relatives.
abstract: Nucleocytoplasmic large DNA viruses (NCLDVs) are eukaryotic viruses with large genomes (100 kb-2.5 Mb), which include giant Mimivirus, Megavirus and Pandoravirus. NCLDVs are known to infect animals, protists and phytoplankton but were never described as pathogens of land plants. Here, we show that the bryophyte Physcomitrella patens and the lycophyte Selaginella moellendorffii have open reading frames (ORFs) with high phylogenetic affinities to NCLDV homologues. The P. patens genes are clustered in DNA stretches (up to 13 kb) containing up to 16 NCLDV-like ORFs. Molecular evolution analysis suggests that the NCLDV-like regions were acquired by horizontal gene transfer from distinct but closely related viruses that possibly define a new family of NCLDVs. Transcriptomics and DNA methylation data indicate that the NCLDV-like regions are transcriptionally inactive and are highly cytosine methylated through a mechanism not relying on small RNAs. Altogether, our data show that members of NCLDV have infected land plants.
authors: 1] INRA, UR1164 URGI-Research Unit in Genomics-Info, INRA de Versailles-Grignon, Route de Saint-Cyr, Versailles 78026, France [2].
authors: Florian
authors: F
authors: Maumus
authors: INRA, UMR1318 INRA-AgroParisTech, INRA de Versailles-Grignon, Route de Saint-Cyr, Versailles 78026, France.
authors: Aline
authors: A
authors: Epert
authors: INRA, UMR1318 INRA-AgroParisTech, INRA de Versailles-Grignon, Route de Saint-Cyr, Versailles 78026, France.
authors: Fabien
authors: F
authors: Nogué
authors: 1] Laboratoire Information Structurale and Génomique, UMR7256 CNRS, Aix-Marseille Université, Marseille FR-13385, France [2].
authors: Guillaume
authors: G
authors: Blanc
mesh_terms: D019068:Bryopsida / Q000235:genetics* / Q000821:virology; D019175:DNA Methylation; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D018745:Genome, Plant / Q000235:genetics*; D056686:Mimiviridae / Q000235:genetics*; D016366:Open Reading Frames / Q000235:genetics*; D010935:Plant Diseases / Q000235:genetics*; D010942:Plant Viruses; D032503:Selaginellaceae / Q000235:genetics* / Q000821:virology; D012689:Sequence Homology, Nucleic Acid