Targeted Modulation of Eukaryotic Release Factor 1 (OseRF1) by an RNA Aptamer Enhances Drought Adaptation in Rice

Area of Science:

• Molecular Biology
• Plant Science
• Biotechnology

Background:

• Drought stress significantly limits rice yield, creating a need for enhanced stress resilience strategies.
• Translation termination is identified as a key regulatory point for cellular adaptation to stress.

Purpose of the Study:

• To identify and characterize a novel RNA aptamer (RTAR) capable of modulating translation termination for improved drought tolerance in rice.
• To investigate the mechanism by which RTAR interacts with rice eukaryotic release factor 1 (OseRF1) and its impact on protein synthesis fidelity.

Main Methods:

• Systematic Evolution of Ligands by Exponential Enrichment (SELEX) to isolate the RTAR aptamer.
• Structural and functional analyses to determine RTAR's binding site and inhibitory mechanism on OseRF1.
• Ribosome profiling (Ribo-seq) and gene expression analysis to assess transcriptome-wide effects.
• Generation and testing of transgenic rice lines under controlled and soil-based drought conditions.

Main Results:

• RTAR selectively binds to OseRF1, inhibiting stop-codon recognition and promoting translational readthrough.
• RTAR expression enhances drought tolerance in rice seedlings and stable transgenic lines, improving survival and chlorophyll retention.
• Evidence of altered translation termination fidelity and C-terminal protein extensions in key drought-responsive genes (e.g., OsDR8) in vivo.
• The functional importance of the OseRF1 Arg46 binding pocket was confirmed using site-specific mutants.

Conclusions:

• RTAR serves as a precise and reversible modulator of translation termination, offering a new tool for crop improvement.
• Targeting OseRF1 with RTAR represents a promising strategy for engineering enhanced drought adaptation in rice and potentially other crops.