Abiotic stresses such as soil salinity cause major reductions in annual agricultural yields worldwide. It has been estimated that, in the United States alone, soil salinity reduces irrigated crop yields by 20-30% annually. With few exceptions, crop plants are unable to adapt to the ionic and osmotic stresses induced by elevated levels of salt in the soil. While genetic variation for plant growth in salinity (salt tolerance) exists, little is known about the genes and pathways underlying this variation. This project will use: 1) evolutionary analyses of species within the Brassicaceae (the mustard family) to understand mechanisms that drive plant adaptation to soil salinity, 2) molecular genetic comparisons of Arabidopsis thaliana and Eutrema salsugineum (Thellungiella halophila), related species within the Brassicaceae with extreme differences in salt tolerance, to understand if changes in proteins or gene regulatory sequences drive this adaptive evolution and, 3) analyses of natural variation within Arabidopsis accessions to uncover the relationship between genetic variants and plant adaptation to salinity. Results from these studies will identify the genes, pathways, and modifications needed to enhance crop growth and yield in saline environments.
This project will also be used to enhance the infrastructure of research, training, and outreach through: 1) continued instruction of undergraduate and graduate students and training of postdoctoral researchers at the University of Arizona, 2) collaboration with the University of Arizona Graduate Fellows in K-12 Education, the BIOTECH Project, and the KEYS Summer Internship Program, to produce integrated teaching modules to introduce evolutionary, genetic, and genomic approaches for investigating plant adaptation in K-12 classrooms and to provide teachers and high school students with research experiences and, 3) participation in the Southern Arizona Math, Science, and Technology Funfest program (6,000 4th-8th graders) and the University of Arizona Plant Science Family Nights.