Functional Analysis of the Autophagy-Related Gene OsATG4b in Rice Grain Chalkiness Regulation

Area of Science:

• Plant Biology
• Genetics
• Molecular Biology

Background:

• Grain chalkiness is a major concern for rice quality, affecting consumer acceptance and breeder efforts.
• Understanding the genetic factors influencing grain development is crucial for improving rice.

Purpose of the Study:

• To investigate the function of the autophagy-related gene OsATG4b in rice grain development and chalkiness.
• To determine the molecular mechanisms by which OsATG4b affects grain quality.

Main Methods:

• Gene expression analysis of OsATG4b in rice endosperm.
• Phenotypic characterization of OsATG4b-overexpressing and knockout mutant rice lines.
• Ultrastructure analysis of endosperm and seed storage component evaluation.

Main Results:

• OsATG4b expression is predominantly in the endosperm.
• Overexpression of OsATG4b reduced grain chalkiness, while knockout mutants showed increased chalkiness.
• Mutants exhibited loosely packed starch granules, aberrant protein bodies, and reduced storage proteins, with OsATG4b regulating storage protein biosynthesis genes.

Conclusions:

• OsATG4b plays a critical role in regulating rice grain chalkiness.
• The gene influences grain quality by affecting starch granule packing and seed storage protein levels.
• OsATG4b is a potential target for breeding improved rice varieties with reduced chalkiness.