Examining the molecular mechanisms contributing to the success of an invasive species across different ecosystems

Invasive species provide an opportune system to investigate how populations respond to new environments. While the impacts of invasive species increase annually, gaps in our understanding of how these species adapt to introduced areas remain. Using the perennial forb Gypsophila paniculata, we investigated how invasive species respond to different environments. Since its introduction to North America, babys breath (G. paniculata) has spread throughout the northwestern United States and western Canada. We used an RNA-seq approach to explore how molecular processes contribute to the success of invasive populations that share similar genetic backgrounds across distinct habitats. Transcription profiles were constructed for root, stem, and leaf tissue from seedlings collected from a sand dune ecosystem in Petoskey, MI (PSMI) and a sagebrush ecosystem in Chelan, WA (CHWA). We assessed differential gene expression and identified SNPs within differentially expressed genes. We identified 1,146 differentially expressed transcripts across all tissues between the two populations. GO processes enriched in PSMI were associated with nutrient starvation, while enriched processes in CHWA were associated with abiotic stress. Only 7.4% of the differentially expressed transcripts contained SNPs differing in allele frequencies of at least 0.5 between the populations. Common garden studies found the two populations differed in germination rate and seedling emergence success, but not in above- and below-ground tissue allocation. Our results suggest the success of G. paniculata across these two environments is likely the result of plasticity in molecular processes responding to different environmental conditions, although some genetic divergence may be contributing to these differences.