Abstract
Endogenous viral elements (EVEs) are the result of heritable horizontal gene transfer from viruses to hosts. In the last years, several EVE integration events were reported in plants by the exponential availability of sequenced genomes. Eucalyptus grandis is a forest tree species with a sequenced genome that is poorly studied in terms of evolution and mobile genetic elements composition. Here we report the characterization of E. grandis endogenous viral element 1 (EgEVE_1), a transcriptionally active EVE with a size of 5,664 bp. Phylogenetic analysis and genomic distribution demonstrated that EgEVE_1 is a newly described member of the Caulimoviridae family, distinct from the recently characterized plant Florendoviruses. Genomic distribution of EgEVE_1 and Florendovirus is also distinct. EgEVE_1 qPCR quantification in Eucalyptus urophylla suggests that this genome has more EgEVE_1 copies than E. grandis. EgEVE_1 transcriptional activity was demonstrated by RT-qPCR in five Eucalyptus species and one intrageneric hybrid. We also identified that Eucalyptus EVEs can generate small RNAs (sRNAs),that might be involved in de novo DNA methylation and virus resistance. Our data suggest that EVE families in Eucalyptus have distinct properties, and we provide the first comparative analysis of EVEs in Eucalyptus genomes.
Highlights
In the last years, the burst of plant genome sequences has uncovered innumerable cases of horizontal gene transfer (HGT)
In this study, using publicly available genomic and transcriptomic E. grandis resources, we report the molecular characterization of this new Endogenous Viral Elements (EVEs) family, named E. grandis endogenous viral element 1 (EgEVE_1)
We evaluated the transcriptional activity of EgEVE1 reverse transcriptase in E. grandis, E. brassiana, E. saligna, E. tereticornis, E. urophylla and in one hybrid E. grandis x E. urophylla
Summary
The burst of plant genome sequences has uncovered innumerable cases of horizontal gene transfer (HGT). HGT is the DNA flow between unrelated species. Viruses play important roles in HGT, once many studies detected viral sequences integrated into several plant genomes (Bertsch et al, 2009; Geering et al, 2014; Fonseca et al, 2016). These viral DNA sequences present within the genomes of non-viral organisms are known as Endogenous Viral Elements (EVEs; Holmes, 2011).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
