Bacterial Symbionts in Ceratitis capitata

SIMPLE SUMMARY: The Mediterranean fly (Medfly), Ceratitis capitata, is considered one of the world’s most destructive fruit pests, as it can attack commercially important fruit, thus causing considerable economic damages, estimated to be more than 2 billion dollars annually. The yield reductions are mainly due to the damage incurred when larvae feed directly on the pulp, inducing the premature fruit drop. Additionally, oviposition holes facilitate secondary fungal and bacterial infections, further reducing the yields. Integrated pest management (IPM) strategies for medfly control are highly dependent on the use of insecticides, which, however, pose environmental concerns. Alternative strategies include the Sterile Insect Technique (SIT), which aims to eliminate or suppress pest insects without using pesticides. Lately, the medfly microbiota has been explored to develop new control strategies for insect pests and insect vectors. Here, we report the characterization of the microbial communities associated with selected organs of three different populations of C. capitata to identify possible candidates for a Symbiotic Control approach. Our findings provide new knowledge about the microbiota associated with C. capitata and stress the characterization of microbial symbionts as possible tools for a Symbiotic Control approach to implementing the pest management programs. ABSTRACT: Ceratitis capitata (Diptera: Tephritidae) is responsible for extensive damage in agriculture with important economic losses. Several strategies have been proposed to control this insect pest including insecticides and the Sterile Insect Technique. Traditional control methods should be implemented by innovative tools, among which those based on insect symbionts seem very promising. Our study aimed to investigate, through the 16S Miseq analysis, the microbial communities associated with selected organs in three different medfly populations to identify possible candidates to develop symbiont-based control approaches. Our results confirm that Klebsiella and Providencia are the dominant bacteria in guts, while a more diversified microbial community has been detected in reproductive organs. Concertedly, we revealed for the first time the presence of Chroococcidiopsis and Propionibacterium as stable components of the medfly’s microbiota. Additionally, in the reproductive organs, we detected Asaia, a bacterium already proposed as a tool in the Symbiotic Control of Vector-Borne Diseases. A strain of Asaia, genetically modified to produce a green fluorescent protein, was used to ascertain the ability of Asaia to colonize specific organs of C. capitata. Our study lays the foundation for the development of control methods for C. capitata based on the use of symbiont bacteria.