Coordination of host and endosymbiont gene expression governs endosymbiont growth and elimination in the cereal weevilSitophilusspp

Abstract

AbstractBackgroundInsects living in nutritionally poor environments often establish long-term relationships with intracellular bacteria that supplement their diets and improve their adaptive and invasive powers. Even though these symbiotic associations have been extensively studied on physiological, ecological and evolutionary levels, few studies have focused on the molecular dialogue between host and endosymbionts to identify genes and pathways involved in endosymbiosis control and dynamics throughout host development.ResultsWe simultaneously analyzed host and endosymbiont gene expression during the life cycle of the cereal weevilSitophilus oryzae, from larval stages to adults, with a particular emphasis on emerging adults where the endosymbiontSodalis pierantoniusexperiences a contrasted growth-climax-elimination dynamics. We unraveled a constant arms race in which different biological functions are intertwined and coregulated across both partners. These include immunity, metabolism, metal control, apoptosis, and bacterial stress response.ConclusionsThe study of these tightly regulated functions, which are at the center of symbiotic regulations, provides evidence on how hosts and bacteria finely tune their gene expression and respond to different physiological challenges constrained by insect development in a nutritionally limited ecological niche.Graphical Abstract