Improved soybean oil quality by targeted mutagenesis of the fatty acid desaturase 2 gene family

Plant Biotechnol J. 2014 Sep;12(7):934-40. doi: 10.1111/pbi.12201. Epub 2014 May 23.

Abstract

Soybean oil is high in polyunsaturated fats and is often partially hydrogenated to increase its shelf life and improve oxidative stability. The trans-fatty acids produced through hydrogenation pose a health threat. Soybean lines that are low in polyunsaturated fats were generated by introducing mutations in two fatty acid desaturase 2 genes (FAD2-1A and FAD2-1B), which in the seed convert the monounsaturated fat, oleic acid, to the polyunsaturated fat, linoleic acid. Transcription activator-like effector nucleases (TALENs) were engineered to recognize and cleave conserved DNA sequences in both genes. In four of 19 transgenic soybean lines expressing the TALENs, mutations in FAD2-1A and FAD2-1B were observed in DNA extracted from leaf tissue; three of the four lines transmitted heritable FAD2-1 mutations to the next generation. The fatty acid profile of the seed was dramatically changed in plants homozygous for mutations in both FAD2-1A and FAD2-1B: oleic acid increased from 20% to 80% and linoleic acid decreased from 50% to under 4%. Further, mutant plants were identified that lacked the TALEN transgene and only carried the targeted mutations. The ability to create a valuable trait in a single generation through targeted modification of a gene family demonstrates the power of TALENs for genome engineering and crop improvement.

Keywords: fatty acid desaturase; linoleic acid; metabolic engineering; oleic acid; targeted mutagenesis.

MeSH terms

  • Base Sequence
  • Fatty Acid Desaturases / genetics*
  • Fatty Acids / metabolism
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Mutation
  • Nutritive Value / genetics
  • Oleic Acid / metabolism
  • Plant Proteins / genetics*
  • Plants, Genetically Modified / chemistry
  • Plants, Genetically Modified / metabolism
  • Seeds / enzymology
  • Seeds / genetics
  • Seeds / metabolism
  • Sequence Alignment
  • Soybean Oil / chemistry*
  • Soybeans / enzymology
  • Soybeans / genetics*
  • Soybeans / metabolism

Substances

  • Fatty Acids
  • Plant Proteins
  • Oleic Acid
  • Soybean Oil
  • Fatty Acid Desaturases