Biosynthesis of Essential Polyunsaturated Fatty Acids in Wheat Triggered by Expression of Artificial Gene

Abstract

The artificial gene D6D encoding the enzyme ∆6desaturase was designed and synthesized using the sequence of the same gene from the fungus Thamnidium elegans. The original start codon was replaced by the signal sequence derived from the wheat gene for high-molecular-weight glutenin subunit and the codon usage was completely changed for optimal expression in wheat. Synthesized artificial D6D gene was delivered into plants of the spring wheat line CY-45 and the gene itself, as well as transcribed D6D mRNA were confirmed in plants of T0 and T1 generations. The desired product of the wheat genetic modification by artificial D6D gene was the γ-linolenic acid. Its presence was confirmed in mature grains of transgenic wheat plants in the amount 0.04%–0.32% (v/v) of the total amount of fatty acids. Both newly synthesized γ-linolenic acid and stearidonic acid have been detected also in leaves, stems, roots, awns, paleas, rachillas, and immature grains of the T1 generation as well as in immature and mature grains of the T2 generation. Contents of γ-linolenic acid and stearidonic acid varied in range 0%–1.40% (v/v) and 0%–1.53% (v/v) from the total amount of fatty acids, respectively. This approach has opened the pathway of desaturation of fatty acids and production of essential polyunsaturated fatty acids in wheat.

Keywords

• wheat
• essential fatty acid
• γ-linolenic acid
• ∆6desaturase
• artificial gene
• transgene