Synthetic horizontal gene transfer for ecosystem restoration.

Restoring endangered ecosystems has become a pressing issue as the effects of global warming continue to harm existing communities. During the last decade, several studies have suggested the use of synthetic biology as a tool to protect these biodiverse communities by increasing their functionality. A critical example concerns soil microbiome communities in drylands, where increasing water retention by some of the constituent species could effectively protect the ecosystem from abrupt degradation. However, how to effectively deploy a functional synthetic construct that can scale its impact to the community level remains an open question. Recent experimental research has designed recombinant gene plasmids with the capacity to horizontally transfer across soil microbial communities. Here, we explore the impacts of synthetic horizontal gene transfer in models of ecological consortia. We define a consumer-resource model in which species can share an engineered plasmid that reduces resource loss, effectively coupling multispecies dynamics and gene spreading. By doing so, we identify a wide range of parameters and the optimal gene transfer conditions for which the intervention promotes biodiversity and biomass gains, while regulating gene propagation and the spread of engineered organisms. Our work provides a first step toward understanding the mechanisms and opportunities of engineered plasmid transfer in multispecies ecological communities.