Emerging strategies to improve heat stress tolerance in crops

While extensive research has documented the frequency and agricultural impacts of summer heatwaves, the exclusive focus on seasonal extremes fails to account for crop-specific vulnerabilities across developmental stages. The authors utilize historical global temperature data to showcase the frequency of extreme high temperatures in major crop-producing regions (including rice, maize, wheat, and soybean), providing essential temperature data for studying how temperature influences crop yield and quality. Based on these findings, the authors highlight that crops are exposed to heat stress at various growth stages, such as tillering and panicle differentiation, which have not been adequately acknowledged. Meanwhile, the authors propose six strategies to mitigate the impact of heat stress on crop yield and quality.

1. Identify natural variations and introduce into major cultivated varieties: This remains the primary strategy for addressing heat stress. However, assessing the breeding value of natural thermotolerant variations presents a significant challenge. The authors recommend exploring underutilized thermotolerant alleles and conducting multi-year, multi-location production trials within current major crop varieties and their adapted ecological regions. These trials should comprehensively evaluate heat tolerance and the impact on agronomic traits, ensuring that enhancing heat tolerance does not compromise overall crop production performance.
2. Develop breeding potential for thermomemory phenotypes: Stress memory refers to a crop's ability to develop stronger resistance after encountering non-lethal stress. This enhanced resistance not only protects crops from the same type of stress but also improves tolerance to other environmental stresses. Future research could focus on identifying beneficial natural variations of heat memory-related genes and exploring their potential applications to increase crop tolerance to frequent high temperatures or other environmental stresses.
3. Co-improve growth development and heat tolerance: Achieving concurrent improvements in crop growth and heat tolerance is challenging, as crops often prioritize resource allocation to stress responses under high-temperature conditions, which may hinder growth and development. Future research should aim to identify the key factors and molecular switches that regulate both stress responses and growth development. The goal is to discover superior natural variations that enable the co-improvement of growth development and heat tolerance in crops.
4. Identify Superior Alleles for Tolerance to Multiple Environmental Stresses: In natural crop environments, crops are often exposed to multiple stresses, such as heat and drought. Therefore, merely addressing heat stress is insufficient to cope with the full spectrum of environmental challenges. Future research should explore the combined response mechanisms to different stresses and identify exceptional gene resources for multi-stress tolerance
5. Create novel favorable variations: Using artificial intelligence design and continuous evolution systems for proteins or nucleic acids presents an opportunity to efficiently create superior allelic variations that do not naturally exist. This approach could facilitate the development of new, beneficial traits to enhance heat tolerance in crops.
6. Develop plant heat tolerance regulators: Currently, improving crop heat tolerance through genetic modification faces many challenges, so developing low-cost and environmentally friendly plant regulators has become another important strategy to alleviate heat stress.

Lastly, the authors highlight that global warming will lead to increased nighttime temperatures, which will also negatively impact crop yield and food quality. However, research on nighttime heat stress or combined day-night heat stress remains limited. The key factors regulating day-night heat tolerance have yet to be identified, making this an urgent research area for the future.

See the article:

Emerging strategies to improve heat stress tolerance in crops

https://link.springer.com/article/10.1007/s42994-024-00195-z