Characterization of the bacterial community structure in Cecropia-obligate Azteca ants using 454 pyrosequencing

Title: Characterization of bacterial community structure in Cecropia-obligate Azteca ants using 454 pyrosequencing Authors: Alissa Hanshew and Cameron Currie This study presents the first characterization of the microbial community of the myrmecophyte Cecropia and the aggressive Azteca ants that provide the plant with protection from herbivores. Despite the ubiquity of this system in neotropical environments and status as a model for animal-plant mutualisms, no study has investigated the microbiota of this ant-plant mutualism. We first used 454 pyrosequencing of the 16S rRNA gene to characterize the bacterial communities associated with Azteca worker ants, larvae, pupae, and domatia samples from the Cecropia tree inhabited by each colony. Additional comparisons were made to assess which aspect of the symbiotic interaction might explain the diversity of bacteria found, including the specific Azteca species sampled, the species of Cecropia tree they were inhabiting, and their geographic region of origin. Our results identified a number of bacterial taxa that appear to be unique for Cecropia-obligate Azteca ants. Each of the Azteca ants were dominated by taxa identified as Proteobacteria, however, further comparisons show that each of the ants sampled harbored vastly different Alphaproteobacteria taxa. Of the genera identified, Wolbachia and Rickettsia dominate, along with a taxa in the order Rhizobiales currently unclassifiable to the genus level. This work is the first description of the bacteria associated with Cecropia-obligate Azteca ants, and adds to the growing body of research demonstrating that insects are reliant upon symbiotic bacteria for a number of functions, and that biogeography is an important factor contributing to the structure of the microbial communities harbored within this symbiotic system.