Investigating GRXS17-mediated Thermotolerance through Genetic Screen of Suppressors

Elevated temperature in climate has made survival challenging for crop plants and heat stress has caused a global decline in crop yields. Several signaling components, which control plant reactions to heat stress, have been recognized. However, we are still far from understanding the complete picture behind thermotolerance. The Hirschi Lab identified a Monothiol Glutaredoxin protein, AtGRXS17, as being a key component in heat response and a nexus between thermotolerance and auxin reponse. The exact mechanism by which GRXS17 mediates plant response to heat is unknown. The focus of this project is to identify proteins that are involved in GRXS17-mediated heat tolerance through suppressor screening in the atgrxs17 background. AtGRXS17 knock out mutants show stunted growth in both leaves and roots in high temperatures compared to the wild-type. We treat about 5000 atgrxs17 seeds with ethyl methanesulfonate (EMS) which causes random mutations in the genome. We then grow these seeds (M1 generation) in soil and harvest the seeds (M2 generation). The M2 generation is plated in an elevated temperature of 28° C to screen for genetic suppressors of GRXS17. We select revertants that exhibit wild-type characteristics as possible suppressors. The suppressor can then be crossed with the wild-type line to later map for the mutation.

If the exact mechanism in which GRXS17 regulates heat responses is understood, an increase in plant hardiness and quality can be attained. We hope to see an effect on crop yield as we relate this research to Biofortification strategies to boost crop’s resistance to harsh temperatures.