OsWRKY53-OsGT1 Module Regulates Rice Tiller Development and Is Involved in Fine-Tuning Strigolactone Signaling.

Area of Science:

• Plant genetics and breeding
• Molecular plant science
• Agricultural biotechnology

Background:

• Plant architecture traits like height, tiller number, and leaf angle significantly impact rice yield.
• Identifying genes that simultaneously control these traits is crucial for crop improvement.
• OsWRKY53 was previously linked to plant height and leaf angle regulation through brassinosteroid signaling.

Purpose of the Study:

• To investigate the role of OsWRKY53 in regulating rice tiller number.
• To elucidate the molecular mechanisms underlying OsWRKY53's function in tillering.
• To explore the interaction between OsWRKY53, strigolactone signaling, and tiller development.

Main Methods:

• Genetic analysis of the oswrky53 mutant.
• Molecular cloning and gene expression analysis.
• Protein-protein interaction studies (e.g., yeast two-hybrid, co-immunoprecipitation).
• Strigolactone content and sensitivity assays.

Main Results:

• The oswrky53 mutant displays semi-dwarf stature and increased tiller number, a desirable agronomic combination.
• OsWRKY53 directly activates OsTB1, a suppressor of tiller formation.
• OsWRKY53 interacts with OsGT1, synergistically enhancing OsTB1 expression and reducing tillering.
• The mutant shows altered strigolactone (SL) sensitivity and content, with SL promoting OsWRKY53 degradation.
• OsWRKY53 negatively regulates SL biosynthesis, indicating its role in SL pathway fine-tuning.
• OsGT1 allele variation (OsGT1^581T) influences tillering capacity across rice subspecies.

Conclusions:

• OsWRKY53 is identified as a novel negative regulator of tillering in rice.
• A molecular mechanism involving OsWRKY53, OsGT1, OsTB1, and strigolactone signaling controls tiller development.
• OsWRKY53 offers a promising genetic target for developing semi-dwarf, high-tillering rice varieties.