Molecular Mechanics Underlying Tepary Bean Responses to Drought Stress

As climate change progresses, rising global temperatures continue to increase stress on the world’s agricultural systems. The common bean (whose varieties include green, navy, black, kidney, and pinto beans) has proven particularly susceptible to these changes. In fact, over two-thirds of the world’s legumes are expected to be at risk (Zaulda et al., 2022). The tepary bean, a sister species of the common bean, is indigenous to the southwestern United States and Mexico and has emerged as a viable source of genetic variation for increasing the common bean’s resistance to abiotic stress. Previously, we have identified genes that underlie tepary bean’s resistance to drought stress using forward genetics. Here, we conducted experiments to validate individual genes’ contributions towards drought resilience. Firstly, we successfully validated a protocol for cowpea mosaic virus-induced gene silencing (VIGS) in tepary bean and cowpea. Secondly, we evaluated tepary bean accessions previously classified as stress-resilient or susceptible in the PhenoSight facility for their responses to drought stress. Finally, we screened T-DNA insertion mutants in Arabidopsis of genes homologous to tepary bean genes associated with drought stress resilience. Our results were promising on several fronts. Thanks to our successful validation of the VIGS protocol and evaluation of tepary accessions as tolerant and susceptible to drought stress, we are now targeting drought stress genes using VIGS in tepary beans. Further, our evaluation of Arabidopsis mutants revealed the potential role of several genes in response to osmotic stress at a large evolutionary scale, which may allow us to gain further insight into the broad application of our findings. These and future studies will help us advance our understanding of what makes tepary bean so resilient to drought stress, allowing the identification of future breeding targets in legumes and beyond, and contributing to greater global food security.

I am immensely grateful to have been placed in the Julkowska Lab. The culture of Magda’s lab and the effort she put into her mentorship made me feel welcomed, respected, and safe to make mistakes or not know it all right away. When I arrived, I wrote down three things I hoped to accomplish during this experience: a better understanding of my career goals, to gain confidence, and to increase my knowledge in depth, breadth, and application. I know I have accomplished all three of these goals. This REU has helped me learn about careers in plant science and agriculture I was previously unaware of. The daunting goal of exploring grad school seems somewhat lessened by the information and experience I gained, and I feel much more at home in the lab setting. While no experience is without its challenges, Magda and the BTI staff’s tireless efforts have made the experience worthwhile, and I am truly thankful.