A Genetically Modified Anti-Plasmodium Bacterium Is Harmless to the Foragers of the Stingless Bee Partamona helleri

Paratransgenesis consists of genetically engineering an insect symbiont to control vector-borne diseases. Biosafety assessments are a prerequisite for the use of genetically modified organisms (GMOs). Assessments rely on the measurement of the possible impacts of GMOs on different organisms, including beneficial organisms, such as pollinators. The bacterium Serratia AS1 has been genetically modified to express anti-Plasmodium effector proteins and does not impose a fitness cost on mosquitoes that carry it. In the present study, we assessed the impact of this bacterium on the native bee Partamona helleri (Meliponini), an ecologically important species in Brazil. Serratia eGFP AS1 (recombinant strain) or a wild strain of Serratia marcescens were suspended in a sucrose solution and fed to foragers, followed by measurements of survival, feeding rate, and behavior (walking and flying). These bacteria did not change any of the variables measured at 24, 72, and 144 h after the onset of the experiment. Recombinant and wild bacteria were detected in the homogenates of digestive tract during the 144 h period analyzed, but their numbers decreased with time. The recombinant strain was detected in the midgut at 24 h and in the hindgut at 72 h and 144 h after the onset of the experiment under the fluorescent microscope. As reported for mosquitoes, Serratia eGFP AS1 did not compromise the foragers of P. helleri, an ecologically relevant bee.