Elevating RNA m⁵C methylation provides a promising strategy for crop productivity

Area of Science:

• Plant molecular biology
• Epigenetics
• Agricultural science

Background:

• RNA 5-methylcytidine (m⁵C) is a crucial epitranscriptomic modification impacting mRNA post-transcriptional regulation.
• The role of m⁵C in plant agronomic traits is an emerging area of research.

Purpose of the Study:

• To investigate the function of the RNA m⁵C demethylase OsNOP2 in rice.
• To determine the impact of OsNOP2 knockout on m⁵C levels and agronomic traits.
• To explore the potential of OsNOP2 as a target for crop genetic improvement.

Main Methods:

• In vitro and in planta functional assays of OsNOP2 RNA m⁵C demethylase activity.
• Generation and phenotypic analysis of OsNOP2 knockout (OsNOP2-KO) rice lines.
• Analysis of transcript translation efficiency and agronomic traits under various conditions (normal, heat, salinity).
• Comparative analysis of OsNOP2 orthologs in wheat and tomato.

Main Results:

• OsNOP2 knockout leads to elevated m⁵C levels in rice mRNA.
• Enhanced m⁵C levels promote translation of transcripts involved in carbon assimilation and nitrogen metabolism.
• OsNOP2-KO significantly increases grain yield (approx. 28%) under normal conditions.
• Increased yield traits are maintained under heat and saline stress.
• OsNOP2 knockout enhances yield in multiple rice varieties, wheat, and tomato, indicating functional conservation.

Conclusions:

• OsNOP2 functions as an RNA m⁵C demethylase, and its knockout epigenetically enhances plant growth.
• Elevated m⁵C levels improve carbon assimilation and nitrogen utilization efficiency.
• OsNOP2 represents a promising target for genetic strategies to improve yield and stress resilience in major crops.