Submitted to: Plant Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2022
Publication Date: 6/2/2022
Citation: Sprague, S.A., Tamang, T., Steiner, T., Wu, Q., Hu, Y., Kakeshpour, T., Park, J., Yang, J., Peng, Z., Bergkamp, B., Somayanda, I., Peterson, M., Garcia, E., Hao, Y., Amand, P., Bai, G., Nakata, P.A., Rieu, I., Jackson, D.P., Cheng, N., Valent, B., Hirschi, K.D., Jagadish, S., Liu, S., White, F.F., Park, S. 2022. Redox-engineering enhances maize thermotolerance and grain yield in the field. Plant Biotechnology. https://doi.org/10.1111/pbi.13866.
DOI: https://doi.org/10.1111/pbi.13866

Interpretive Summary: Climate change and food security are preeminent global concerns. Given the inverse relationship between rising temperatures and crop yield, research must be done to address this problem of increasing food productivity in warming global conditions. Maize is the highest yielding crop in the world and, despite a subtropical ancestral origin, maize flowers are hypersensitive to high temperature. In this manuscript we report the generation of an engineered corn line that displays increased kernel set, resulting in a 6-fold increase in yield when challenged with heat stress under both laboratory and field grown conditions. To our knowledge these corn lines are the most thermotolerant generated to date.

Technical Abstract: Increasing populations and temperatures are expected to escalate food demands beyond production capacities, and the development of maize lines with better performance under heat stress is desirable. Here, we report that constitutive ectopic expression of a heterologous glutaredoxin S17 from Arabidopsis thaliana (AtGRXS17) can provide thermotolerance in maize through enhanced chaperone activity and modulation of heat stress-associated gene expression. The thermotolerant maize lines had increased protection against protein damage and yielded a 6-fold increase in grain production in comparison to the non-transgenic counterparts under heat stress field conditions. The maize lines also displayed thermotolerance in the reproductive stages, resulting in improved pollen germination and the higher fidelity of fertilized ovules under heat stress conditions. Our results present a robust and simple strategy for meeting rising yield demands in maize and, possibly, other crop species in a warming global environment.