NSF PRFB FY23: Dissecting the holobiont: exploring how genetics, environments, and microbiomes contribute to emergent host phenotypes

Hardison, Emily A, Goleta CA

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2023, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment, and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. Microbes can have many effects on animals, including everything from their digestion to their survival in extreme temperatures. For example, green frog tadpoles raised in water without microbes were more affected by high temperatures and had a higher chance of dying from heat stress than tadpoles grown in water containing wild pond microbes. This suggests that their microbiome – the microbes living in and on tadpoles – shapes the frog’s physiology and tolerance to extreme conditions. Green frogs live in ponds across the entire East Coast of the USA, from colder northern states to much warmer southern states. An unknown question is: are the microbes living in ponds and their resident tadpoles different in the North and South? And if so, do northern microbes help frogs thrive in colder water or southern microbes help them in warmer water? Using a combination of observations and experiments, the fellow will study green frog microbiomes across their geographic range, to see if they help the frogs to thrive across a wide range of temperatures. This work is important for predicting how animals will respond to environmental change and helping amphibian conservation efforts. To address these questions, the fellow will start by comparing water and tadpole microbiomes from ponds along the species' range. By pairing this analysis with habitat characterization, the fellow will explore drivers of variation in microbial communities from tadpole pond habitat. Building on this fieldwork, the fellow will conduct a captive breeding study using green frogs from their northern and southern range limits and perform a factorial experiment, rearing their offspring in tanks amended with microbes collected from northern or southern ponds, followed by measuring tadpole thermal performance. Through these activities, the fellow will gain new understanding of the factors shaping microbiome composition (i.e., host genetics, environmental conditions, and environmental microbes) and their impacts on intraspecific variation in the frog microbiome and emergent thermal phenotypes. Through this project, the fellow will also gain invaluable training in bioinformatics, microbiome physiology, and lab leadership. Finally, the fellow will host mentorship workshops to promote inclusive and informed mentorship practices and will advise and participate in conservation-focused STEM education programs. 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.