Ectopic expression of a soybean phytase in developing seeds of Glycine max to improve phosphorus availability

• Published in: Plant molecular biology 2004-12, Vol.56 (6), p.895-904
• Main Authors: Chiera, J.M, Finer, J.J, Grabau, E.A
• Format: Article
• Language: English
• Subjects: 6-Phytase - genetics; 6-Phytase - metabolism; Antigens, Plant; Chromatography, High Pressure Liquid; complementary DNA; embryo culture; Enzymatic activity; enzyme activity; gene expression; Gene Expression Regulation, Developmental; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; genetic transformation; Globulins - genetics; Glycine max; Glycine max - enzymology; Glycine max - genetics; Glycine max - metabolism; Liquid chromatography; messenger RNA; nutrient content; Nutrition; phosphorus; Phosphorus - metabolism; phytases; phytic acid; Phytic Acid - metabolism; Plants, Genetically Modified; Promoter Regions, Genetic - genetics; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; seed development; Seed Storage Proteins; Seeds; Seeds - enzymology; Seeds - genetics; Seeds - growth & development; Soybean Proteins - genetics; Soybeans; transgenic plants
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/s11103-004-5293-6

A transgenic approach was used to alter soybean seed phytate content by expressing a soybean phytase gene (GmPhy) during seed development to degrade accumulating phytic acid (IP6). An expression vector containing the soybean phytase cDNA controlled by the seed-specific beta-conglycinin promoter (alpha'-subunit) was used to transform embryogenic soybean cultures. Plants from four independent transgenic lines were analyzed for transgene integration and seed IP6 levels. The reduction in IP6 levels in transgenic seeds compared to control 'Jack' soybeans ranged from 12.6 to 24.8% as determined by HPLC. A low copy transformant was propagated to the T4 generation and examined in more detail for phytase expression and enzyme activity during seed development. Expression of phytase mRNA and phytase activity increased during seed development, consistent with the use of an embryo-specific promoter. Ectopic phytase expression during seed development offers potential as an effective strategy for reducing phytate content in soybean seed.