Background:
Salt marshes are areas of intertidal grasslands. They are important for coast maintenance, erosion control,
carbon regulation, and they supply raw materials and food. One plant that dominates the North American
wetlands is Spartina alterniflora. This smooth cordgrass plays a large role in wetland maintenance through soil stabilization and nutrient recycling [1]. In salt marshes, there is a gradient in the phenotypic height of S.
alterniflora, wherein the plants located closer to the ocean are taller while the plants growing closer to the
shoreline are shorter [2]. Plants of this species with different height phenotypes have different microbial
populations [2, 3]. These populations are predominantly composed of sulfur-oxidizing and sulfate-reducing
bacteria [3]. The bulk soil metagenomes of bulk sediment, rhizosphere, and endosphere associated with S.
alterniflora sediment compartments of tall and short phenotypes were obtained by the Kostka lab and their
microbiome was analyzed [3].
To improve our understanding of the ecological interactions within the salt marsh associated to S. alterniflora, we are studying the viral populations found in the different sediment compartments and plant phenotypes. Viruses are the most prominent biological entities in the ocean and impact their surrounding ecosystems [4]. Through the lytic cycle, viruses infect the surrounding microbial populations, replicate within them, and then lyse the host while their progeny burst into the environment. Through this process, the viruses regulate the population densities of surrounding microbes, impacting the diversity of microbial populations [5,6]. In the lysogenic cycle, the genome of temperate phage integrates into its host’s and replicates with it, with no lysis occurring. These temperate phages can benefit their host by carrying Auxiliary Metabolic Genes (AMGs) which can play a role in boosting host metabolism [4]. With this project, we aim to characterize the viral populations associated with S. alterniflora, and the role they play in the maintenance of S. alterniflora in salt marshes. We intend to do so by studying the prevalence, taxonomy, host associations, and gene composition of viral populations in the three different sediment compartments at the different height phenotypes, and analyzing the relationship between the viruses, the microbial populations, and S. alterniflora.