Extensin-like Protein OsPEX1 Modulates Grain Filling in Rice

Area of Science:

• Plant Biology
• Molecular Genetics
• Agricultural Science

Background:

• Grain filling is critical for rice yield and quality.
• The molecular mechanisms of grain filling are not fully understood.
• Mutants with defective grain filling offer insights into this process.

Purpose of the Study:

• To functionally analyze the grain-filling defective rice mutant *pex1*.
• To elucidate the role of *OsPEX1* in rice grain development.
• To understand the impact of *OsPEX1* on starch accumulation and assimilate transport.

Main Methods:

• Phenotypic analysis of *pex1* mutants.
• Microscopic examination of nucellar projection cells.
• Gene expression analysis during grain filling.
• Subcellular localization of OsPEX1 protein.

Main Results:

• *pex1* mutants exhibit floury seeds and reduced grain-filling rates.
• Impaired starch accumulation in the endosperm and defective assimilate transport were observed.
• Irregular nucellar projection cells suggest compromised transfer of photosynthetic products.
• Downregulation of key grain-filling genes in *pex1* mutants correlates with reduced filling rates.
• OsPEX1 protein is associated with the endoplasmic reticulum.

Conclusions:

• *OsPEX1* plays a vital role in regulating rice grain filling.
• Defective OsPEX1 function disrupts starch synthesis and assimilate translocation.
• Understanding OsPEX1's function can help improve rice grain yield and quality.