Oral Paper

         Functional Genetics/Genomics

Draba albertina illustrates adaptive responses to stress

Presenting Author
Nicolette Sipperly
Description
To persist in a new or changing environment, plants must adapt to obtain resource requirements for reproduction and survival. These new traits may express as change in plant growth habit structure or morphology, as well as differences in regulatory genes or protein coding genes. Draba albertina (Brassicaceae) is a widespread species found in diverse environments including in the mountainous west United States. Phenotypic and genetic differences across local D. albertina populations reflect, at least in part, adaptation to their unique conditions. Here I explore phenotypic variation in flowering time, root shoot ratio, and lignin content as well as genetic variation in three populations of D. albertina. I also compare gene expression across the two populations that most diverge in their exposure to insect herbivores, water stress, and human disturbance. Population genetics analyses reveal protein coding differences, suggesting local adaptation to a gradient of stressors such as insect pressure, water stress and human disturbance. Differentially expressed genes in the leaves concentrated in biosynthesis of secondary metabolites pathway and in particular, in the phenylpropanoid pathway, which is responsible for biosynthesis of lignin, flavonoids and a variety of aromatic metabolites in response to biotic and abiotic stimuli. Phenotype and gene expression analyses show the population exposed the most stressors to has faster time to flower and differences in expression of cell cycle genes in bolting tissue, changes in growth patterns that can decrease the stress of insect herbivory and water scarcity. Under greater stress from insect herbivores and human disturbance, D. albertina have evolved greater resilience by decreasing lignin in its stem tissue and modifying cell wall components, possibly making the nutrient inside of their cells more mobile and readily recycled in the case of insect damage. D. albertina provides a model that illustrates genetic and expression mechanisms that allow plants to survive and reproduce in stressful conditions that include defense, escape through time of development, and resilience.