A low-methane rice with high-yield potential realized via optimized carbon partitioning

Area of Science:

• Agricultural Science
• Environmental Science
• Plant Biology

Background:

• Global rice cultivation is a major source of anthropogenic methane emissions due to anaerobic soil conditions and root exudates.
• Natural variations in methane emission rates among rice cultivars suggest potential for genetic improvement.
• Plant physiology, specifically sugar allocation, is hypothesized to influence both crop yield and methane production.

Purpose of the Study:

• To develop high-yielding rice lines with reduced methane emissions.
• To investigate the role of sugar allocation in modulating methane release from rice plants.
• To identify molecular markers associated with low-methane emission traits in rice.

Main Methods:

• Cross-breeding a low-methane variety (Heijing 5) with high-yielding elite varieties.
• Analyzing carbon storage in above-ground tissues and carbohydrate levels in rhizospheric soil.
• Utilizing transcriptome analysis to examine sugar transporter gene expression (SUT-C, SWEET).
• Quantifying methane emissions from progeny lines under controlled and field conditions.

Main Results:

• Progeny lines exhibited increased carbon storage in above-ground tissues compared to parent varieties.
• Reduced levels of glucose and other carbohydrates were detected in the rhizosphere of progeny lines.
• Elevated expression of sugar transporters (SUT-C, SWEET) was observed in progeny lines.
• Methane emissions were reduced by approximately 70% in the developed rice lines.

Conclusions:

• Three independent low-methane emission rice lines with high yield potential have been successfully developed.
• Altered carbon allocation, specifically increased shoot storage and modified root exudation, contributes to reduced methane emissions.
• The study provides a molecular basis for understanding sugar transport's role in methane mitigation in rice cultivation.