Hydrogen peroxide regulates the Osa-miR156-OsSPL2/OsTIFY11b module in rice

Area of Science:

• Plant Molecular Biology
• Plant Stress Physiology
• Biochemistry

Background:

• Environmental stresses induce reactive oxygen species (ROS), like hydrogen peroxide (H₂O₂), in rice (Oryza sativa L.).
• MicroRNAs (miRNAs) are critical regulators of plant responses to environmental stress.

Purpose of the Study:

• To investigate the function of H₂O₂-regulated miRNAs in rice.
• To elucidate the molecular mechanisms underlying H₂O₂-induced stress responses in rice.

Main Methods:

• Small RNA deep sequencing to identify H₂O₂-responsive miRNAs.
• Bioinformatic analysis of rice transcriptome and degradome databases to identify miRNA targets.
• Agroinfiltration, transient expression assays, and yeast two-hybrid assays to confirm molecular interactions.
• Analysis of transgenic rice plants overexpressing miR156.

Main Results:

• H₂O₂ treatment led to decreased levels of miR156 in rice.
• OsSPL2 and OsTIFY11b were identified as direct targets of miR156.
• OsSPL2 and OsTIFY11b proteins interact in the nucleus and regulate the expression of OsRBBI3-3, a proteinase inhibitor involved in plant defense.
• OsTIFY11b further interacts with OsMYC2 in this regulatory pathway.

Conclusions:

• H₂O₂ accumulation suppresses miR156 expression, leading to the induction of its target genes OsSPL2 and OsTIFY11b.
• The OsSPL2 and OsTIFY11b protein complex plays a role in mediating H₂O₂-induced plant defense responses in rice by regulating OsRBBI3-3.