OsROXY2 Regulates Stamen Number Through Interaction with OsbZIP47 in Rice

Area of Science:

• Plant Biology
• Developmental Biology
• Genetics

Background:

• Precise regulation of floral primordia initiation (PI) is crucial for normal flower development.
• The underlying mechanisms governing floral PI are intricate and not fully elucidated.

Purpose of the Study:

• To identify genetic factors regulating floral organ number in rice.
• To elucidate the molecular mechanisms controlling stamen and carpel primordia initiation.

Main Methods:

• Identification and characterization of the rice stamen less (sl) mutant.
• Gene cloning and analysis of OsROXY2 and its homolog OsROXY1.
• Investigating gene interactions using yeast two-hybrid assays and analyzing subcellular localization and expression patterns.
• Phenotypic analysis of single and double mutants (osroxy1, osroxy2, osbzip47).

Main Results:

• The stamen less (sl) mutant exhibits defects in stamen and carpel PI, leading to reduced stamen number and absent carpels.
• STAMENLESS (SL) encodes OsROXY2, a CC-type glutaredoxin essential for stamen PI.
• OsROXY2 interacts with the TGA transcription factor OsbZIP47, which acts as a negative regulator of stamen PI.
• The osbzip47 mutant shows an increased stamen number, contrasting with OsROXY2's role.

Conclusions:

• OsROXY2 regulates stamen number through interaction with OsbZIP47, establishing a GRX-TGA-mediated floral organ number regulation mechanism.
• This mechanism is conserved between monocots (rice) and eudicots.
• The study provides novel insights into the genetic control of floral organogenesis.