Habitat Visualization and Genomic Analysis of “Candidatus Pantoea carbekii,” the Primary Symbiont of the Brown Marmorated Stink Bug

kenyon, laura j. ; meulia, tea ; sabree, zakee, l.;

Phytophagous pentatomid insects can negatively impact agricultural productivity and the brown marmorated stink bug (Halyomorpha halys) is an emerging invasive pest responsible for damage to many fruit crops and ornamental plants in North America. Many phytophagous stink bugs, including H. halys, harbor gammaproteobacterial symbionts that likely contribute to host development, and characterization of symbiont transmission/acquisition and their contribution to host fitness may offer alternative strategies for managing pest species. “Candidatus Pantoeacarbekii” is the primary occupant of gastriccecalumin a flanking the distalmid gut ofH. halys insects and it is acquired each generation when nymphs feedon maternal extra chorion secretions following hatching. Insects prevented from symbiont up take exhibit developmental delays and aberrant behaviors. To infer contributions of Ca. P. carbekii toH. halys, the complete genome was sequenced and annotated from a North American H.halys population. Overall, the Ca.P. carbekii genome is nearly one-fourth (1.2Mb) that of free-living congenerics, and retains genes encoding many functions that are potentially host-supportive. Gene content reflects patterns of gene loss/retention typical of intracellular mutualists of plantfeeding insects. Electron and fluorescence in situ microscopic imaging of H. halys egg surfaces revealed that maternal extrac horion secretion swere populated with Ca.P. carbekii cells. The reported findings detail a transgenerational mode of symbiont transmission distinct from that observed for intracellular insect mutualists and illustrate the potential additive functions contributed by the bacterial symbiont to this important agricultural pest