Engineering the chloroplast unfolded protein response to enhance heat stress tolerance in plants

Overview

This research opportunity targets the chloroplast unfolded protein response (cpUPR), a cellular pathway that maintains protein and RNA homeostasis inside chloroplasts during environmental stress. By overexpressing key genes within this pathway, plants can be engineered to better withstand abiotic stresses such as heat and drought, leading to improved growth, enhanced crop fitness, and greater carbon sequestration in field conditions.

The approach is grounded in discoveries from a Chlamydomonas mutant screen that identified genes responding to proteotoxicity and chloroplast damage. These genes overlap with networks activated by high light and heat stress, making them promising targets for engineering stress-tolerant crops. The central premise is that protecting chloroplast function during abiotic stress preserves photosynthetic performance and overall plant viability.

Technical specifications

• Core approach: Overexpression of cpUPR-related genes to maintain protein and RNA homeostasis within chloroplasts during stress conditions
• Model organism validation: Wild-type Chlamydomonas, a highly sensitive cpUPR mutant, and an overexpression mutant tested with and without mycotoxin exposure showed significant protection (p < 0.05) in the overexpression line
• Gene discovery: Screen revealed multiple candidate genes impacting protein and RNA homeostasis, including several unknown genes; approximately half have strong Arabidopsis orthologs
• Translation pathway: Identified genes will be used to engineer overexpression vectors for Arabidopsis transformation, followed by testing under heat and drought stress compared to vector controls
• Crop application: Genes providing the greatest protection in Arabidopsis will be advanced for testing in cereal crops
• Key advantage: Targets both abiotic stresses (heat, drought, high light) and biotic stresses (mycotoxin sensitivity), offering broad-spectrum plant protection

Technology readiness level

The technology is currently at an early-to-mid stage of development. Proof-of-concept validation has been completed in Chlamydomonas, demonstrating that overexpression of a key cpUPR gene provides significant protection against chloroplast stress. The proposed two-year study will advance the work through Arabidopsis transgenic validation under heat and drought stress conditions before translation to cereal crops. This positions the research at a stage suitable for sponsored research collaboration to accelerate gene identification, vector development, and crop translation.