Periodic Reporting for period 4 - MultiLevelLandscape (Multilevel Selection for Specificity and Divergence in Bacteria) Período documentado: 2021-09-01 hasta 2023-02-28 Resumen del contexto y de los objetivos generales del proyecto Social interactions affect the behavior of organisms from bacteria to man. An important aspect of social interaction is communication. Bacteria utilize small molecules to communicate between each other. In many species of bacteria, these chemical signals tend to rapidly evolve to form different communication channel, i.e – a signal made by one strain of bacteria would not be sensed by another. This process requires the co-evolution of the signal molecule and its receptor and hence serves to elucidate the general problem of co-evolution under social selection. Our previous work indicated that the strong evolution of this system is dependent (or at least facilitated) by the selection on multiple levels of organization – the gene itself, it host bacterium (and sometime a host DNA parasite residing within the host bacterium), and the bacterial community. The importance for selection on multiple levels to the evolution of complex traits is widely discussed, but lacks concrete good model systems where it can be observed. Studying bacterial communication has both direct benefit for society, as many bacteria utilize it to control their virulence. It also provides a general avenue for our basic understanding of the evolution of complex social traits in a relatively simple and experimentally amenable model system. The aims of the grant where to:1. Understand the scope of molecular diversity of a model bacterial communication system. This is to be done using advanced molecular screening techniques and high-throughput sequencing.2. Understand the impact of ecology on selection on multiple scales. Especially understanding the effect of spatial organization within a community and horizontal transfer.3. Understanding the molecular paths which allow diversification of communication system in the above mentioned ecologies. Trabajo realizado desde el comienzo del proyecto hasta el final del período abarcado por el informe y los principales resultados hasta la fecha We have been able to greatly extend the understanding of the role of communication in the microbial world. Two specific achievements which greatly moved the field forward are:1. We have shown that bacteria can communicate on very different scales - some communication systems allow large bacterial communities to interact over ranges of hundreds of microns (allowing communication between thousands of cells and more), while other systems are designed for "personal" communication between near-neighbors only (a scale of ~10 cells). We were able to show the difference between wide-range and local communication systems and to show specific functions that need to utilize one of the types and not the other.2. We have significantly extended the role communication can plays in interaction between parasitic elements and viruses that infect bacteria. Specifically, we have shown that virus that infect bacteria can communicate with each other (in different bacteria) to determine whether they want to switch from a dormant state to a more aggressive state where they can infect other bacteria. We also showed that bacterial parasites can manipulate the host as part of their infection cycle and that communication contribute to the decision whether to perform the manipulation or not. Avances que van más allá del estado de la técnica e impacto potencial esperado (incluida la repercusión socioeconómica y las implicaciones sociales más amplias del proyecto hasta la fecha) The project funding period has ended, but many research avenues that were initiated during the project would give fruits in the coming years. A visual illustration of the measurement apparatus used to study the range of signaling
