Current Projects
Traits of soil bacteria predict plant responses to soil moisture
Microbial communities appear to commonly respond to drought in ways that promote plant drought drought tolerance via "microbe-mediated acclimation," but why they do this remains a mystery. To understand this pattern I applied theory on the evolution of cooperation, which traditionally explains pairwise interactions among tightly coevolving partners. I found that byproduct benefits, which occur when traits that favor the survival and reproduction of microbes incidentally benefit plant hosts, can generate fitness alignment between microbes and plants in dry and wet conditions. In other words, microbial traits that promote microbial success in different moisture environments also promote plant success in these same environments, providing a feasible mechanism for why this common but perplexing phenomenon may occur. Relevant papers:
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How rapid microbial responses to stress influence adaptation to stress
In addition to their ecological impacts, rapid microbial responses to stress may alter host evolution by acting as cryptic selective agents. I found that the indirect microbe-mediated effects of stress on natural selection are generally weaker than the direct effects of stress on plant evolution, but can contribute substantially. Furthermore, microbe-mediated effects almost always counteracted the direct effects of stress, suggesting that microbes may buffer plants from extreme swings in the strength of natural selection when the environment shifts. I also detected strong legacy effects of stress-adapted microbes on selection in non-stressful environments, suggesting that past stress may cause longer, persistent effects on plant evolution even post-stress. Lastly, I found that microbe-mediated plant plasticity was usually adaptive, while direct plastic responses to stress were always maladaptive, suggesting that plastic trait shifts may reduce plant fitness under stress in the absence of microbes. Together, these results unveil a cryptic role for microbes in altering the evolutionary trajectory of plants during and after stress, as well as promoting plant acclimation to stress by promoting beneficial plant trait shifts. Relevant papers: |
Agricultural application: How does irrigation interact with microbe-mediated plasticity to influence crop resilience under drought?
If dry-adapted microbes promote adaptive plant responses in the face of drought, then disruption of those microbial communities may have important implication for agricultural crops. For instance, farmers in the midwest are irrigating their fields more frequently in response to higher drought prevalence - if irrigation erodes the ability of microbes to provide crop resilience under drought, which my work and the work of others suggest it may, then it could cause feedbacks that lead to farmers relying on increasing amounts of irrigation. In this project, I test whether irrigation results in microbial communities that provide less benefit to plants under drought. |