Rational Gene Stacking for Seed-Specific Carbon Partitioning to Simultaneously Enhance Lipid and Protein Contents in...

Area of Science:

• Plant Biotechnology
• Crop Science
• Molecular Biology

Background:

• Global population growth necessitates oilseed crops like canola and soybean with enhanced protein and oil content.
• A negative correlation typically exists between seed protein and oil accumulation, posing a challenge for crop improvement.

Purpose of the Study:

• To test the hypothesis that reallocating seed carbon from cellulose to storage compounds via gene stacking can improve both protein and oil content.
• To engineer Arabidopsis thaliana for increased seed protein and oil while reducing cellulose.

Main Methods:

• A three-pronged gene stacking strategy was employed in Arabidopsis thaliana.
• Down-regulation of Arabidopsis CELLULOSE SYNTHASE 1 (AtCESA1) using RNAi to reduce cellulose.
• Over-expression (OE) of Brassica napus DIACYLGLYCEROL ACYLTRANSFERASE 1 (BnDGAT1) variants and Arabidopsis protein biosynthesis genes (AtAAP1, AtALAAT1, AtASN1) to enhance oil and protein.

Main Results:

• The best performing line (AtCESA1-RNAi/BnDGAT1-L441P-OE/AtAAP1-OE) showed a 19.5% increase in crude seed protein and a 3.2% increase in total lipid content.
• A significant 42.2% reduction in cellulose content was observed compared to control lines.
• Seed yield increased by 89% in the engineered line.

Conclusions:

• Fine-tuned gene stacking is an effective strategy to overcome the trade-offs between protein and oil accumulation in seeds.
• This approach demonstrates potential for engineering high-value seed traits in oilseed crops.