Abstract

This study investigates the role of OsProDH in the heat stress tolerance of Bacthom 7 (BT7), a high-quality indica rice variety popular in Northern Vietnam. Using CRISPR/Cas9 gene editing technology, we generated OsProDH mutant BT7 rice lines to elucidate the functional role of this gene in heat stress response. The CRISPR/Cas9- mediated deletion of 39 nucleotides in the OsProDH gene resulted in enhanced proline accumulation and improved heat tolerance in edited plants. Mutant lines exhibited significantly higher survival rates, better water retention, and improved photosynthetic protection under heat-stress conditions compared to wild-type plants. Biochemical analysis revealed reduced reactive oxygen species damage and increased catalase activity in edited plants during heat stress. Importantly, the OsProDH mutation did not negatively impact key agronomic traits, including growth period, plant height, yield components, and grain quality. Our findings demonstrate that targeted editing of OsProDH is an effective strategy for developing heat-tolerant rice varieties without compromising desirable agronomic characteristics. This approach offers a promising solution for enhancing rice resilience to climate change-induced heat stress, contributing to global food security efforts.

Key words: Bacthom 7, CRISPR/Cas9, Heat tolerance, OsProDH, Proline