Disease management strategies:
I will soon start working as a disease ecologist developing models for optimal disease management strategies, including vaccination, for elimination of bovine TB at the cattle-deer interface in Michigan. I will be working on statistical and mechanistic models of disease transmission.
Evolution of virulence:
Why are some pathogens worse and some just bad? This is probably one of the oldest questions that evolutionary biologists have tried to answer. To some extent, the trade-off hypothesis has been successful in explaining and predicting the evolution of virulence in obligatory pathogens. Facultative pathogens, on the other hand, have complicated life-histories which tend to relax the assumed trade-offs of classical virulence evolution models. Besides infecting hosts, facultative pathogens like V. cholera and B. anthrax can survive and grow in the environmental reservoirs. These contrasting ecological settings can result in conflicting selection pressures. There is also the possibility of novel trade-offs to arise in these systems that can alter the course of virulence evolution. For my PhD, I worked on understanding how different trade-offs resulting from facultative pathogen life-history shape evolution of virulence.
Virulence in Stenotrophomonas maltophilia:
Stenotrophomonas maltophilia is an emerging opportunistic pathogen that is associated with different human respiratory diseases, including the Covid-19. In nature, it is found in diverse environments such as soil, water, rhizosphere etc. In environmental pathogens, selection in environmental reservoir can influence pathogen traits, including virulence. This is the basis of coincidental selection hypothesis. S. maltophilia is often found in competitive environments such as rhizosphere, where it competes with other bacteria for food and resources. To counter the competition, it uses type IV secretion system to kill heterologous bacteria in a contact dependent manner. As a part of my PhD, I showed that the type IV secretion system and its associated effectors also influence virulence against Caenorhabditis elegans. Using experimental evolution and genetic manipulation, I showed that coincidental selection for interference competition against heterologous bacteria can help maintain high virulence in S. maltophilia.
Microbiome community assembly:
Given the advancement in sequencing technologies, we can easily identify the community composition of microbiomes. But how do microbes assemble to form a microbiome community? The question of how a community structure is formed and maintained has divided the field of community ecology into two camps. On one camp are those preferring the concept of ecological niche, where species are considered functionally different. On the other camp are neutralists, who assume functional equivalence of species and advocate that random or stochastic birth, death and immigration processes are sufficient in explaining the community structure. Under this project, I am trying to assess how well neutral and niche-based community assembly processes account for patterns of microbiome composition. I am examining this question using the data from Microbiomes of Aquatic, Plant and Soil (MAPS) system in Kansas.