Characterization and expression of codon optimized soybean phytase gene in E. coli.

Area of Science:

• Plant Biotechnology
• Molecular Biology
• Biochemistry

Background:

• Phytic acid in seeds reduces mineral bioavailability and contributes to phosphorus pollution.
• Phytases degrade phytic acid, yielding inositol and phosphate.
• Reducing seed phytate content is a strategy to improve food quality and reduce environmental impact.

Purpose of the Study:

• To reduce phytic acid levels in soybean seeds by ectopically expressing an endogenous phytase gene during seed development.
• To clone and express a functional phytase gene in a suitable system for potential application in soybean transformation.

Main Methods:

• Semi-quantitative RT-PCR was used to analyze phytase gene expression in soybean tissues.
• Full-length phytase cDNA was amplified using splicing by overlap extension (SOE)-PCR.
• The modified phytase gene was cloned into a prokaryotic expression vector (pET-28a+) and expressed in E. coli, with expression confirmed by SDS-PAGE and Western blot.

Main Results:

• Phytase gene transcripts were maximally expressed in germinating soybean cotyledons.
• The amplified phytase cDNA contained an open-reading-frame of 1644 bp with a predicted 547-amino acid protein, sharing conserved domains with other purple acid phosphatases.
• Expression in E. coli yielded a functional phytase, confirmed by bioassay.

Conclusions:

• The study successfully identified and characterized a functional phytase gene from soybean.
• The expressed phytase shows potential for developing low-phytate transgenic soybeans through seed-specific overexpression.
• This approach could enhance nutrient bioavailability in soybean-based foods and mitigate phosphorus pollution.