Genome-Wide Patterns of Bracovirus Chromosomal Integration into Multiple Host Tissues during Parasitism
Héloïse Muller, Mohamed Amine Chebbi, Clémence Bouzar, George Périquet, Taiadjana Fortuna, Paul‐André Calatayud, Bruno Le Rü, Julius Obonyo, Laure Kaiser, Jean‐Michel Drezen, Elisabeth Huguet, Clément Gilbert
Abstract
Bracoviruses are endogenous domesticated viruses of parasitoid wasps that are injected together with wasp eggs into wasp host larvae during parasitism. Several studies have shown that some DNA circles packaged into bracovirus particles become integrated into host somatic genomes during parasitism, but the phenomenon has never been studied using nontargeted approaches. Here, we use bulk Illumina sequencing to systematically characterize and quantify bracovirus circle integrations that occur in four tissues of the Mediterranean corn borer (Sesamia nonagrioides) during parasitism by the Cotesia typhae wasp. Our analysis reveals that all circles containing a HIM integrate at substantial levels (from 12 to 85 integrations per host cell, in total) in all tissues, while other circles do not integrate. In addition to shedding new light on wasp-bracovirus-host interactions, our study supports HIM-mediated chromosomal integration of bracovirus as a possible source of wasp-to-host horizontal transfer, with long-term evolutionary consequences.