Enhanced microRNA accumulation and gene silencing efficiency through optimized precursor base pairing

Area of Science:

• Plant molecular biology
• Gene regulation
• Biotechnology

Background:

• MicroRNAs (miRNAs) are key regulators of gene expression in plants, processed from precursors by DICER-LIKE1 (DCL1).
• Artificial miRNAs (amiRNAs) are tools for targeted gene silencing, but precursor structure optimization is crucial for efficiency.
• The impact of base pairing near DCL1 cleavage sites on amiRNA production is not well understood.

Purpose of the Study:

• To investigate how base pairing at or near DCL1 cleavage sites influences amiRNA production from a minimal precursor.
• To identify structural modifications that enhance amiRNA accumulation and gene silencing efficacy.
• To validate findings in plant models for potential applications in functional genomics and crop engineering.

Main Methods:

• Utilized silencing sensor systems in Nicotiana benthamiana to test amiRNA precursor variants.
• Systematically altered base pairing at naturally mismatched positions near DCL1 cleavage sites.
• Validated enhanced amiRNA production and silencing in Arabidopsis thaliana transgenic lines using deep sequencing.

Main Results:

• Introducing a G-C pair upstream of the mature amiRNA significantly enhanced amiRNA accumulation and silencing efficiency.
• Deep sequencing confirmed accurate processing and predominant release of intended amiRNAs in Arabidopsis.
• The structural modification demonstrated high specificity and efficacy in enhancing amiRNA-mediated gene silencing.

Conclusions:

• A single structural modification in amiRNA precursors can substantially improve amiRNA-mediated gene silencing efficacy.
• The optimized amiRNA platform is suitable for large-scale functional genomics screens.
• This approach facilitates the development of crops with improved resilience to environmental stresses.