Patterns of Bacterial Community Variation across Anatomical, Geographical, and Genetic Distance in Florida Mangroves

Plants are host to a diverse array of non-pathogenic microbes including bacteria and fungi which may act as an "extended phenotype" that provides fitness benefits throughout the life cycle of the plant. These microbial communities influence plant growth, physiology, and survival, though our understanding of their assembly requires further investigation. Plant-associated microbial communities are thought to be derived from both inheritance from parent to offspring, and by acquisition from the local environment. This research focuses on patterns of variation in bacterial communities associated with mangroves, an ecologically and economically invaluable group of plants. Mangroves offer an excellent natural system for these studies due to the multiple evolutionary origins of mangrove habit, ongoing poleward range expansion experienced by several mangrove species, and their unique suite of adaptations to long distance dispersal and establishment in seawater. The chapters herein utilize 16S rRNA gene (iTag) sequencing and microsatellite genotyping to describe variation in bacterial communities across anatomical, geographic, and genetic distance to advance our understanding of how these communities are shaped by the environment and the relatedness of their hosts. If microbial communities are primarily derived via inheritance, then they may act as an extended phenotype which is subject to natural selection, and thus the evolution of the plant itself. Through this research, I aim to answer the question, "Are mangrove-associated bacterial communities more heavily influenced by host environment or host relatedness?" My results indicate that mangrove-associated bacterial communities appear to be influenced more heavily by host environment than by host relatedness, suggesting that interactions between mangroves and their environment may be important in determining mangrove health and functioning.