Presentation Detail

Species Interactions and Coevolution

Garcia, Justine [1], Laughton, Alice [2], Malik, Zayir [3], Parker, Benjamin James [4], Trincot, Claire [3], Chiang, Stephanie [5], Chung, Euisun [3], Gerardo, Nicole [3].

Partner Associations within an Environmentally-Acquired Insect-Bacteria Symbiosis.

Many organisms acquire beneficial microbes (symbionts) from the environment. Such host-symbiont associations can be specific and evolutionarily stable, but they are also prone to lower partner specificity and more partner-switching than vertically transmitted mutualisms. To investigate partner specificity across an environmentally acquired symbiosis, we screened four sympatric broad-headed bug species and their habitat, including soil and food plants, for Burkholderia symbionts. Using 16S sequencing and MLST genotyping, we confirmed that the bacteria hosted by these insects in a specialized section of the midgut are predominantly Burkholderia, though occasionally we recovered non-Burkholderia species. Antimicrobial peptide (AMP) assays suggest that specificity may be driven in part by the ability of AMPs to react selectively towards non-Burkholderia bacteria. Fitness assays confirmed benefits of hosting Burkholderia: one species had faster development and another species had increased survival. The recovered Burkholderia include strains that grouped in clades with other insect symbionts as well as clades that include free-living and rhizosphere-associated Burkholderia. One Burkholderia strain, which is also present in other bug species from distant locations, was highly prevalent in all four pecies. Consequently, there was no significant difference in symbiont strains by host geography. However, there was a significant difference in symbiont strains by host species when only cloned Burkholderia sequences were analyzed, but not when cloned and cultivated Burkholderia sequences were analyzed. Isolation of similar Burkholderia in the broad-headed bugs, the bugs̢۪ leguminous host plant̢۪s root nodules, and the soil indicates that sympatric plant and insect hosts may be associated, in part, with the same symbiont reservoir.

1 - Emory University, Department of Biology, 1510 Clifton Rd. NE, Atlanta, GA, 30322
2 - Queen Mary University of London, School of Biological and Chemical Sciences,, Mile End Road, E1 4NS, London, E1 4NS, UK
3 - Emory University , Department of Biology, 1510 Clifton Rd. NE, Atlanta, GA, 30322, USA
4 - Emory University, Biology, O. Wayne Rollins Research Center, 1510 Clifton Road NE, Room 2006, Atlanta, GA, 30322, United States
5 - Emory University, Biology, 1510 Clifton Rd NE, RRC1174, Atlanta, Georgia, 30322, United States

Keywords:
mutualism
gut symbionts
Burkholderia
Insects.

Presentation Type: Regular Oral Presentation
Session: 111
Location: Cotton B/Snowbird Center
Date: Monday, June 24th, 2013
Time: 11:15 AM
Number: 111004
Abstract ID:1272
Candidate for Awards:W.D. Hamilton Award for Outstanding Student Presentation