EF: Collaborative Research: MTM 2: Marine Invertebrate Microbiome Assembly, Diversification, and Coevolution

Microbes associated with marine invertebrates are of broad interest for establishing the rules of life for host-microbe associations. Although some marine invertebrates host only one or two types of microbes, others host thousands of different kinds of microbes. The project goal is to understand how and why particular microbes are hosted by invertebrates; whether the diversity of these microorganisms is related to the diversity of their hosts; and how these associations change over evolutionary time. The investigators are training graduate, undergraduate, and high school students how to assess microbiome diversity; how to use novel software to search, categorize, and compile data from DNA sequence archives; and how to identify and classify marine invertebrates. They are integrating graduate students and undergraduate students in the development of a high-school-based program to mentor students in the assessment of marine invertebrate biodiversity, training the next generation of scientists in invertebrate biology, host-microbe ecology, and evolutionary data analyses. In addition, research scientists are being trained to use novel data mining and compilation software to address unexplored questions in host-microbe evolution. This project is investigating three ecological and evolutionary processes that structure the biodiversity of microbiomes: assembly, diversification, and coevolution. While previous studies have focused on the host-specificity of microbiomes, the project shifts the perspective from host evolution to microbial evolution. The project is developing models of host-symbiont interactions that function across multiple spatial, temporal, and taxonomic scales. By incorporating theories from evolutionary ecology and metacommunity ecology, the investigators are assessing the relative importance of environmental filtering, host-associated selection pressures, spatial connectivity, microbial competition, cospeciation, and host switching on the assembly of microbiomes. Through the use of phylogenetic comparative methods, the project is testing whether different clades of symbionts and clades of hosts respond to these forces differently. The investigators are examining how microbiomes both impact and respond to the process of host speciation in sympatry and allopatry. To accomplish these goals, novel software and evolutionary models are being developed to support large-scale analyses of microbial diversification and colonization of eukaryotic hosts. These models are being experimentally tested by using a replicated series of settlement structures to examine the assembly of sessile marine invertebrate communities and the assembly of their associated microbiomes. In addition, marine sponges are being used as model organisms to contrast allopatric and sympatric microbiome divergence over evolutionary time. These investigations are enhancing our broader understanding of the roles of microbiomes in sustaining biodiversity. This project is funded by the Understanding the Rules of Life: Microbiome Theory and Mechanisms Program, administered as part of NSF's Ten Big Ideas through the Division of Emerging Frontiers in the Directorate for Biological Sciences. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.