Ecoregion drives intraspecific variation of secondary chemistry in a big sagebrush common garden

Elle Teri , Carolyn Dadabay, Debbie Conner, Kathryn Turner, Brayden Banks, Bryce Richardson, Jennifer Forbey, Leonora Bittleston

Phytochemistry plays an integral role in the health and survival of plants and can mediate community interactions, communication with neighboring plants, protection against disease and herbivores, and attraction of pollinators. We measured non-volatile compounds using liquid chromatography-mass spectrometry (LC-MS) and volatile compounds using gas chromatography (GC) at two different time points from leaves of three subspecies of Artemisia tridentata that were grown in a common garden from seeds sourced from 44 sites. Similar explanatory factors drove the variation in both classes of phytochemicals. While there was an effect of subspecies and cytotype designation, we found that the ecoregion from where the seeds were sourced explained the largest portion of the variation in non-volatile and volatile compounds. Within subspecies, both separation by distance and local climatic factors were correlated with non-volatile chemical profiles. Our results indicate that A. tridentata phytochemistry is genetically determined and differs among individuals of the same subspecies based on the location of origin. These results highlight strong intraspecific variation in phytochemistry for a widespread foundational plant species. Future work may identify and explore the functions of specific compounds, providing further insights into the ecological drivers of A. tridentata phytochemistry.