Research Interests

Human civilization relies heavily on plants for our survival. Plants provide us with food, shelter, fiber, and the atmospheric oxygen we breathe. As human populations and resource consumption increase, we place ever-greater demands on plant communities and are now changing the climates in which they grow. Breeding plants to be efficient and inexpensive carbohydrate delivery systems has had adverse impacts on human health, while simultaneously selecting for undesirable side-effects such as inefficient use of water and nutrients by crop plants. Discovering the evolutionary, ecological and genetic basis for the wide natural variation in how plants acquire and allocate developmental, energetic and nutritional resources will be essential if we are to maintain adaptability in crop plants and natural populations alike. This topic is the focus of research in my laboratory.

Adaptive life history traits in plants, such as growth rates and patterns, reproductive output, and resource allocation, are complex traits. Variation in complex traits is usually influenced by multiple genes (called quantitative trait loci, or QTLs), environment, and their interactions, and these traits typically show a continuous range of variation. Variation in different complex traits is often genetically correlated, and such correlations are expected when life history trade-offs are involved. Thus, we are interested in knowing the locations and ultimately the identities of genes underlying trait variation, the molecular and developmental pathways by which they affect suites of traits, how large their effects are, and how they interact with other genes and the environment.

Specific areas of research in my laboratory include:

Genetics of resource allocation in Arabidopsis lyrata:

The rock cress Arabidopsis lyrata, which is native to parts of North Carolina, is a close relative of Arabidopsis thaliana, an important model plant for genetics research and the first plant to have its complete genome sequenced. Unlike A. thaliana, A. lyrata is an outcrossing perennial that shows strong evidence of local adaptation throughout its North American and Eurasian range. The A. lyrata genome sequence has also been completed recently. This combination of features and genomic resources makes it an ideal plant for investigating the molecular genetic basis of adaptation.

We have found that A. lyrata plants from populations in different environments, such as North Carolina (top) and Norway (center) show major differences in their allocation of resources to reproductive vs. vegetative processes when grown in a common environment (bottom). Thus, A. lyrata provides an outstanding system for dissecting the developmental and genetic basis for variation in resource allocation patterns, which are a key aspect of local adaptation in plants but have not been studied to date in an integrated manner. In collaboration with Outi Savolainen (University of Oulu, Finland), we combined QTL mapping with structural equation modeling to characterize resource allocation trade-offs in Norway x North Carolina crosses tested in both parental environments (Remington et al. 2013). A key finding was that QTL regions affected resource allocation largely by regulating early lateral shoot development, leading to cascading effects on later development. North Carolina alleles increased reproduction and concurrently reduced vegetative development in North Carolina, while reducing both survival and reproduction in Norway. These effects appeared to involve shifts in developmental timing between the two environments, not direct trade-offs between reproduction and survival. Thus, while genes affecting resource allocation appear to have important roles in local adaptation, this may involve complex interactions between developmental patterns and environment instead of traditional models involving direct costs of reproduction. A subsequent study involving the research of two undergraduates (Jennifer Figueroa and Mitali Rane) provided evidence that the developmental differences between populations — essentially variation in the degree of perenniality — involve the amount of time individual shoots grow vegetatively before undergoing reproductive transitions (Remington et al. 2015), which could have very different consequences for survival under long vs. short growing seasons (diagram at left).