I received my B.S. from the Department of Ecology and Evolutionary Biology at the University of Tennessee, Knoxville, and my Ph.D. from the Genetics Department at the University of Georgia in 2006. I was a postdoctoral research associate in Jeff Bennetzen’s lab from 2006-2009, and joined the faculty at in the Biological Sciences Department at the University of Cincinnati in 2010 as an assistant professor. I will join the EEB department at U-M in summer 2013.
My research broadly revolves around the central question ‘Why and how do some organisms persist and adapt to inhospitable environments?’ I work on this topic utilizing species from the morning glory genus, many of which are agricultural weeds. There are four main projects underway in the lab: the evolutionary genomics of plant defense and plant weediness, the influence of the mating system on the evolution of herbicide resistance, and the role of the plant metagenome on adaptation.
1. The evolution of plant defense
The combination of modern genomic approaches with traditional quantitative and ecological genetics gives us the ability to glean a deeper understanding of phenomena that may limit or slow the rate of adaptive evolution, i.e. evolutionary constraints. Central to current evolutionary theory is the idea that covariation among traits, or trade-offs, may act as evolutionary constraints. However, we currently have an immature understanding of how such trade-offs evolve. Recently, a trade-off between two defense characters -- resistance, the ability to remain undamaged, and tolerance, the ability to maintain fitness when damaged -- was uncovered in Ipomoea purpurea, the common morning glory, upon challenge with the herbicide RoundUp. The integrated goals of this research are thus to understand the evolutionary scenarios under which the trade-off in defense may evolve and to determine where in the biological hierarchy such trade-offs are apparent.
2. The impact of a variable mating system on the evolution of herbicide resistance
The evolution of herbicide resistance in a weed is impacted by many important life-history factors, such as the mating system, reproductive output, and gene flow. While many inferences regarding herbicide resistance evolution have been predicted using theoretical models, the dynamic nature of some life history traits, such as variability in the mating system, has been largely ignored. Shu-mei Chang (UGA) and I are working together to understand how variability in the mating system can impact herbicide resistance evolution in I. purpurea, the common morning glory. We will utilize empirical assessments of the mating system, the potential for gene flow among populations, and the potential impact of fitness costs to guide the development of a theoretical model for predicting the spread of herbicide resistance in nature. The long-term goal of this work is to develop a theoretical framework that will be applicable to any weed-herbicide system.
3. The evolution of weediness: a quantitative genetic perspective
Baker (1974) identified a suite of traits that define ‘weedy’ species, such as rapid growth, high fitness, plasticity and tolerance. He developed this list of characters by comparing the life-history traits of congeneric weedy plants. Despite the widespread interest in Baker’s work, few researchers have explicitly investigated the evolutionary potential of such traits within a species. Lindsay Chaney (University of Cincinnati) and I are examining the evolvability of Baker’s ‘weediness’ traits in I. purpurea using the principles of quantitative genetics and field and greenhouse common garden studies.
4. The plant metagenome and plant adaptation
Interactions between plants and their associated soil microbes can influence plant productivity, community composition, and ultimately the biodiversity of natural systems. While the ecological dynamics of above- and below-ground interactions are widely studied, the role of the microbial soil community on plant adaptation has been less interrogated. In collaboration with Jeff Bennetzen (UGA), Ryan Percifield (WVU) and Srini Chaluvadi (UGA), I am utilizing a sequencing approach to characterize the maize microbiome, with the broad goal of determining how microbial communities might change according to environmental perturbations and host genotype. We are continuing this line of research in the lab by utilizing the variation in flower color phenotypes among individuals of I. purpurea to investigate the impact of plant anthocyanins on microbial communities, and likewise, the impact that microbial manipulations might have on host plant fitness.