Land Disturbance Influences Seed-Microbe Associations in a Semi-Arid Ecosystem: Microbial Recruitment and Student Engagement

Abstract

All terrestrial plants in natural and altered ecosystems form symbiotic relationships with microbes. The outcomes of these relationships can be detrimental or beneficial, depending on the confluence of plant genotypes, microbial genotypes, and environmental factors. This thesis focuses on the identification of beneficial microbes that infect seeds in the context of natural and altered environments, and describes how that topic can be used as a platform for a STEM-focused outreach experience for high school students. I first examined the abundance, diversity, and composition of soilborne fungi that infect seeds of a restoration plant, focusing on gradients of land degradation at the Santa Rita Experimental Range (SRER) of southeastern Arizona. I tested the predictions that (1) beneficial microbes would differ as a function of land disturbance, and (2) such effects of disturbance would be mitigated by plant cover. I identified a set of potentially beneficial microbes that may be used in revegetation strategies in disturbed soils. I then translated this experimental approach to form the centerpoint of a multidisciplinary outreach program, which I developed and implemented as an immersive summer program that combines scientific investigation with outreach to underrepresented youth in STEM. Thus this thesis addresses both a scientific question of applied significance as well as a societal need for training and diversification in STEM.