Responses to environmental variation and change can be facilitated or constrained by the genetic basis of adaptations that mediate organism-environment interactions. This research aims to understand and interpret the genetics of functional adaptive biodiversity by integrating analyses at multiple levels of functional trait variation (DNA sequence, gene expression, phenotypes) with data on the environmental, ecological, and evolutionary history of an entire clade of species: Solanum section Lycopersicum (the wild tomatoes). The project focuses on two traits critical to plant-environment interactions: leaf ecophysiology (which influences plant responses to water, light, and carbon dioxide), and constitutive and induced defense responses (which influence the interaction between plants and their natural predators). Both traits differ within and among Solanum species, likely as the result of rapid adaptive change. Using 'next generation' sequencing technologies to quantify DNA sequence and gene expression differences among genotypes and environmental conditions, the project has three components: 1) Comparative transcriptomics (i.e., gene expression profiling) which will provide a evolutionary genomics framework for understanding genetic variation in the group, and identify candidate genes for important ecological transitions among species; 2) Experimental transcriptomics of gene expression responses to both benign (unstressed; noninduced) and stressed (drought-stressed; induced defense) conditions, which will identify molecular responses to ecologically-relevant environments, and evaluate the genetic constraints on current and future evolutionary responses critical to organism-environment interactions; and 3) Integration of results from this study with existing data to generate a core set of loci underpinning functional responses to abiotic and biotic environmental variation, and to develop an integrated understanding of natural adaptive trait variation across an entire group of species.
Global environmental change is expected to fundamentally alter patterns of biodiversity, but predicting the direction and magnitude of this change is extremely difficult. This research aims to understand how current biodiversity is shaped by, and reacts to, environmental variation. The sequence and trait data uncovered will contribute to understanding how plants are able to respond to and cope with stress imposed by both their physical environment and by their predators. The project will also contribute to human resources by training researchers in a broad set of skills at the interface of experimental genetics, genomics, and bioinformatics. This research focuses on the wild tomatoes, a diverse group of Andean species within the economically important genus Solanum. Uncovering the genetic basis of diversification is particularly pertinent in the Andean biological hotspot, where the impacts of land-use and climate change threaten a cradle of biodiversity that holds an estimated 12% of global flowering plant diversity. In addition, by examining the wild relatives of several important crop species, including tomato, potato, and pepper, this research has the potential to identify valuable natural variation that confers plant tolerance to critical environmental stresses.
