PhD Student Louisiana State University Baton Rouge, Louisiana
Body of Abstract: The accumulation of salt and depletion of essential nutrients such as phosphorus in soils are important challenges for agriculture. These problems are expected to intensify with climate change due to groundwater contamination with salt and relying on non-renewable sources of phosphorus for fertilizer. Plant responses to low phosphorus and high salt stress are typically studied individually; however, they often coexist in nature as combined stresses. Therefore, it is important to understand how plants adapt to these combined stresses and how we can design crops that show resilient growth in poor soils. Wild plants that are already adapted to these stresses can provide insight on mechanisms to enhance resilient crop growth. Schrenkiella parvula is an extremophyte model in the Brassicaceae family, closely related to Arabidopsis thaliana and mustard family crops. In this study, we examined short-term physiological and transcriptomic responses of S. parvula to understand its potential adaptive mechanisms in response to low phosphorus and high salt combined stresses. We used young seedlings of S. parvula grown on nutrient supplemented agar transferred to high salt and low phosphorus conditions. These plants were subjected to growth assays and transcriptomic profiling after grown for ten days in control, single, or combined stress conditions. These short-term treatments resulted in fewer differentially expressed genes compared to the single stress given as low phosphorus in the growth medium. The observed physiological responses supported the transcriptomic results for root growth predictions. S. parvula was more responsive at the transcriptome level to high salt than to low phosphorus conditions when individual stress conditions were compared within our experimental design. Additionally, our results identified several nutrient signaling and recycling pathways active under stress conditions. Ongoing research is planned to investigate how these short-term responses are changed with long-term exposure to similar stress conditions.