RESEARCH
We aim to develop a sophisticated understanding of how microbes compete within a host environment. We approach research from the perspective that applied pathosystems can be leveraged to advance basic knowledge regarding microbial ecology, and that basic ecological principles and processes can be leveraged to improve management of plant diseases. Below are some of the major areas of focus within the lab.
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Suppressive Phyllosphere - Interative Microbiome Passaging in Plant System
Microbial communities, known as microbiomes, play a crucial role in plant growth and health. Deciphering the dynamics of the microbial communities and their interactions with the host plant will have important implications for developing novel tools and strategies to enhance plant resilience towards disease and environmental stresses. Recently, we have established a framework that demonstrates disease suppression can be achieved via serial transferring (i.e., iterative passaging) of the foliar microbiome in the tomato-bacterial speck pathosystem. Building on this work, we continue to 1) quantify and analyze the efficacy of the identified suppressive microbial community against bacterial speck disease caused by Pseudmonas synringae pv. tomato (Pto); 2) evaluate the efficacy of the suppressive microbial community against other Pto strains; 3) investigate whether and how the framework of iterative microbiome passaging can be applied to fungal pathosystems, such as tomato early blight caused by Alternaria solani and Alternaria tomatophila. We have leveraged high-throughput sequencing to identify community members hypothesized to contribute to disease suppression and are currently working to isolate these organisms to directly assess their contribution.
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BACTERIOCIN ECOLOGY AND EVOLUTION
Despite over a century of research, there is a yet-to-be fulfilled promise of effective and sustainable biological control agent (BCA)-based plant disease management. We believe this results in part from lacking an understanding of the connection between BCA environmental fitness and biocontrol efficacy. Bacteriocins, like most antagonistic traits, are naturally evolved to aid the success of one organism at the expense of a competitor. However, these traits cannot be expressed willy-nilly, since they are costly to produce. Thus, if we want to know how to employ a microbe with a desired antagonistic trait, we would first want to know when and where within the host environment that trait provides a fitness benefit. Moreover, understanding how the dynamics underlying the broader scale community interactions related to toxin production and sensitivity, from the individual leaf to the regional scale will allow us to better predict how pathogen populations are likely to respond to introduction of a narrow-spectrum toxin, such as a bacteriocin. To close this knowledge gap, we are working with a number of different pathosystems, including mushroom blotch, bacterial speck of tomato, and brown spot and halo blight of common bean. Our approaches include paired strain competition within host environments and targeted sequencing of natural communities.
