miR396b/GRF6 module contributes to salt tolerance in rice.

Area of Science:

• Plant Biology
• Genetics
• Agricultural Science

Background:

• Salinity stress severely impacts crop yield and global food security.
• Developing salt-tolerant, high-yield crop varieties is crucial for meeting rising food demands.
• The miR396b/GRF6 module previously enhanced rice yield by altering inflorescence architecture.

Purpose of the Study:

• To investigate the role of the miR396b/GRF6 module in enhancing rice salt tolerance.
• To elucidate the molecular mechanisms underlying miR396b/GRF6-mediated salt tolerance.
• To identify genetic regulators interacting with the miR396b/GRF6 module in response to salt stress.

Main Methods:

• Generation and analysis of MIM396 and OE-GRF6 transgenic rice lines.
• Measurement of reactive oxygen species (ROS) levels and antioxidant enzyme activities (CAT, SOD, POD).
• Transcriptome analysis, Chromatin immunoprecipitation sequencing (ChIP-seq), and promoter binding assays to identify regulatory interactions.

Main Results:

• MIM396 and OE-GRF6 transgenic lines showed significantly increased survival rates (48.0% and 74.4%) under salt stress compared to wild type.
• Transgenic plants exhibited reduced hydrogen peroxide (H2O2) accumulation and enhanced ROS-scavenging enzyme activities.
• ZNF9 was identified as a negative regulator binding to the miR396b promoter, and MYB3R was identified as a downstream target of the miR396b/GRF6 module, with its overexpression enhancing salt tolerance.

Conclusions:

• The miR396b/GRF6 module plays a significant role in improving rice salt tolerance.
• The study elucidated a regulatory network involving ZNF9, miR396b/GRF6, and MYB3R in rice salt stress response.
• These findings provide valuable genetic resources for breeding high-yield, salt-tolerant rice varieties.