Selection of DNA Aptamers for Root Exudate l-Serine Using Multiple Selection Strategies

Area of Science:

• Agricultural biosensing
• Molecular biology
• Biotechnology

Background:

• Crops release root exudates signaling their health status.
• l-Serine is a biomarker for nitrogen uptake in wheat and canola.
• Accurate monitoring of crop nutrient needs is crucial for efficient agriculture.

Purpose of the Study:

• To develop robust DNA aptamers that bind to l-serine.
• To create a biosensor for precise l-serine quantification in agricultural settings.
• To enhance crop management through nutrient monitoring.

Main Methods:

• Systematic Evolution of Ligands by EXponential enrichment (SELEX) was employed using three distinct DNA libraries.
• SELEX experiments included randomized SELEX, redirected SELEX, and original SELEX approaches.
• Aptamer sequences were optimized through truncation and conversion into nuclease-resistant Spiegelmers.

Main Results:

• All SELEX strategies yielded l-serine-binding aptamers with micromolar affinity.
• The Red.1 aptamer showed an initial K-d of 7.9 ± 3.6 μM, improved to 5.2 ± 2.7 μM after truncation.
• A Spiegelmer derivative exhibited a K-d of 2.0 ± 0.8 μM, demonstrating enhanced binding and stability.

Conclusions:

• Developed l-serine-binding aptamers possess suitable affinity and stability for biosensor applications.
• The engineered Spiegelmer is a promising candidate for integration into agricultural biosensors.
• This technology can significantly improve the precision of crop nutrient management.