OsPHI-2 Controls Rice Growth and Development Through OSH1-Dependent Transcriptional Repression.

Area of Science:

• Plant Biology
• Agricultural Science
• Genetics

Background:

• Phosphorus (P) is essential for crop growth, but its scarcity limits productivity.
• Mechanisms controlling P allocation between plant parts are not fully understood.

Purpose of the Study:

• To identify regulators of phosphorus allocation in rice (Oryza sativa L.).
• To understand the role of OsPH-2 in plant adaptation to low phosphorus conditions.

Main Methods:

• Transcriptional analysis and promoter binding assays to study OSH1-OsPH-2 interaction.
• CRISPR gene editing to create OsPH-2 knockout and overexpression rice lines.
• Haplotype analysis to investigate subspecies-specific P remobilization.

Main Results:

• OsPH-2 is repressed by OSH1 under low phosphorus (LP) conditions.
• OsPH-2 knockout lines showed increased biomass and adaptive resource allocation under LP.
• Overexpression of OsPH-2 impaired panicle development and reduced grain yield.
• OsPH-2 modulates expression of P transporters and vacuolar effluxes, prioritizing reproductive sinks.
• Indica rice subspecies rapidly suppress OsPH-2 under P deficiency for enhanced panicle P remobilization.

Conclusions:

• The OSH1-OsPH-2 regulatory module fine-tunes phosphorus partitioning in rice.
• OsPH-2 plays a key role in plant adaptation to phosphorus-deficient environments.
• OsPH-2 represents a potential genetic target for enhancing phosphorus-use efficiency in rice breeding programs.