Nicole Gerardo*1, Tarik Acevedo1, Tiffanie Alcaide1, Greg Fricker1, Justine Garcia1
Insects have long served as key systems for addressing questions concerning the ecological and evolutionary underpinnings of both harmful and beneficial host-microbe interactions. Complete understanding of the dynamics and importance of these associations benefits from systems that include both experimentally tractable microbes and experimentally tractable hosts. Here, we exploit systems in which true bugs associate with primary bacterial symbionts that can be cultivated and experimentally introduced to hosts. We explore symbiont variation in natural populations, the consequences of the association for host fitness, and the impacts of the infection on the ability of the insects to vector a bacterial plant pathogen. We demonstrate that dominant members of the hosts’ symbiotic community are bacteria in the genus Burkholderia. Despite the fact that fitness assays indicate that association with Burkholderia is critical for host fitness, the symbionts are not transmitted directly to the offspring but are acquired from the environment. Burkholderia can suppress growth of vectored pathogens both in vitro and in vivo, however the dynamics of such suppression are dependent on strain-level variation, suggesting the outcome of symbiont-pathogen coinfection are likely complex in natural populations.
1Department of Biology, Emory University, Atlanta, GA, USA