UC San Diego

Horizontal Gene Transfer (HGT) is the transfer of bacterial genes from one bacteria to another and is a vital tool that allows various microbes to adapt rapidly to new environments by exchanging potentially beneficial genes. Previously, our lab identified a large mobile genetic region putatively involved in iron acquisition (termed RUSTI for iRon Update Siderophore Transport Island) which we believe is horizontally transferred in the cheese community. The RUSTI region is on a much larger mobile genetic region called an integrative and conjugative element (ICE). We termed the RUSTI-containing ICE for Proteobacteria the ProteoRUSTI ICE. To test if RUSTI is indeed horizontally transferred we co-cultured a Vibrio casei carrying the ProteoRUSTI ICE with three cheese-rind isolated Proteobacteria: Psycrobacter, Vibrio sp., and Pseudoalteromonas. These bacteria were found to not carry the ProteoRUSTI ICE. We unfortunately did not observe an HGT event between Vibrio casei and the ProteoRUSTI ICE negative bacteria. However, this masters laid the ground work on how to design and organize HGT experiments in the cheese rind. These findings are important for the development of our model because they highlight the characteristics of RUSTI in various ways. Creating a better understanding of how mobile genetic elements such as RUSTI behave in species-species interactions provides us insight into how the microbes or their genes in more complex microbial communities may interact with one another.