Speaker: Irene Newton (Indiana University, Bloomington)
Symbiosis is a unifying feature for life on the planet - from the mitochondrion to the microbiome, eukaryotes have formed symbiotic relationships with bacteria to expand their niches, their metabolic functions, and their cellular capabilities. Regardless of fitness outcome, however, all invading microbes must perform three important tasks: 1) initiate contact with the correct host, 2) colonize and replicate within that host, and 3) disseminate to new hosts. One bacterial symbiont that has mastered these tasks is Wolbachia pipientis, an alpha-proteobacterial obligate intracellular infection of filarial nematodes, insects, and other arthropods. Estimates place infection frequencies for Wolbachia at upwards of 40-60%, making it the most prevalent infection on the planet. But how has Wolbachia managed to infect so many different hosts? In this seminar I will present data on the molecular toolkit used by Wolbachia to manipulate host biology and persist intracellularly. I will show you how Wolbachia uses a molecular machine - the type IV secretion system - to inject an actin bundler into the host to modify host actin during infection, facilitating transmission to the next generation. I will present data from the biochemical assay to high throughput sequencing to Drosophila genetics. Finally, I will touch on the evolution of this molecular toolkit and what it can teach us about Wolbachia's success and prevalence.