Transgenic maize plants expressing a fungal phytase gene
- 1.2k Downloads
Maize seeds are the major ingredient of commercial pig and poultry feed. Phosphorus in maize seeds exists predominately in the form of phytate. Phytate phosphorus is not available to monogastric animals and phosphate supplementation is required for optimal animal growth. Undigested phytate in animal manure is considered a major source of phosphorus pollution to the environment from agricultural production. Microbial phytase produced by fermentation as a feed additive is widely used to manage the nutritional and environmental problems caused by phytate, but the approach is associated with production costs for the enzyme and requirement of special cares in feed processing and diet formulation. An alternative approach would be to produce plant seeds that contain high phytase activities. We have over-expressed Aspergillus niger phyA2 gene in maize seeds using a construct driven by the maize embryo-specific globulin-1 promoter. Low-copy-number transgenic lines with simple integration patterns were identified. Western-blot analysis showed that the maize-expressed phytase protein was smaller than that expressed in yeast, apparently due to different glycosylation. Phytase activity in transgenic maize seeds reached approximately 2,200 units per kg seed, about a 50-fold increase compared to non-transgenic maize seeds. The phytase expression was stable across four generations. The transgenic seeds germinated normally. Our results show that the phytase expression lines can be used for development of new maize hybrids to improve phosphorus availability and reduce the impact of animal production on the environment.
KeywordsMaize Phytate Fungal phytase phyA2 Transgenic plant
We thank Mr. Li Denghai, Prof. Zhang Shihuang and Dr. Li Mingshun for their help. We acknowledge Key National Project of China Crop Genetic Resources and Gene Improvement for providing greenhouse and other facilities. This work was partially supported by the National Basic Research and development Program of China (973 Program) (No. 2005CB120905) and a research grant from Pioneer Hi-Bred International, a DuPont Company.
- Armstrong CL, Green CE, Philips RL (1991) Development and availability of germplasm with high type II culture formation response. Maize Genet Coop News Lett 65:92–93Google Scholar
- Austin S, Bingham ET, Koegel RG, Mathews DE, Shahan MN, Straub RJ (1994) An overview of a feasibility study for the production of industrial enzymes in transgenic alfalfa. In: Bajpai RK, Prokop A (eds) Recombinant DNA Technology II. New York Academy of Sciences, New York, pp 234–244Google Scholar
- Coello P, Maughan JP, Mendoza A, Philip R, Bollinger DW, Veum TL, Vodkin LO, Polacco JC (2001) Generation of low phytic acid Arabidopsis seeds expressing an E. coli phytase during embryo development. Seed Sci Res 11:285–291Google Scholar
- Cosgrove DJ (1966) The chemistry and biochemistry of inositol polyphosphates. Rev Pure Appl Chem 16:209–215Google Scholar
- Drakakaki G, Marcel S, Glahn RP, Lund EK, Pariagh S, Fisher R, Christou P, Stoger E (2005) Endosperm specific co-expression of recombinant soybean ferritin and Aspergillus phytase in maize results in significant increases in the levels of bioavailable iron. Plant Mol Biol 59:869–880PubMedCrossRefGoogle Scholar
- Jongbloed AW, Kemme PA, Mroz Z (1996) Phytase in swine rations: impact on nutrition and environment. In: BASF Technical Symposium. January 29, 1996, Des Moines, IA, BASF, Mount Olive, NJ, pp 44–69Google Scholar
- Ravindran V, Bryden WL, Kornegay ET (1995) Phytates: occurrence, bioavailability and implications in poultry nutrition. Poult Avain Bio Rev 6:125–143Google Scholar
- Tomes DT (1995) Direct DNA transfer into plant cell via microprojectile bombardment. In: Gamborg OL, Philipps GC (eds) Plant cell tissue and organ culture: fundamental methods. Springer-Verlag Publisher, Berlin, pp 197–213Google Scholar
- Van Droogenbroeck B, Cao J, Stadlmann J, Altmann F, Colanesi S, Hillmer S, Robinson DG, Van Lerberge E, Terryn N, Van Montagu M, Liang M, Depicker A, De Jaeger G (2007) Aberrant localization and underglycosylation of highly accumulating single-chain Fv-Fc antibodies in transgenic Arabidopsis seeds. Proc Natl Acad Sci USA 104:1430–1435PubMedCrossRefGoogle Scholar
- Wyss M, Brugger R, Kronenberger A, Remy R, Fimbel R, Oesterhelt G, Lehmann M, van Loon AP (1999a) Biophysical characterization of fungal phytases (myo-inositol hexakisphosphate phosphohydrolases): molecular size, glycosylation pattern, and engineering of proteolytic resistance. Appl Environ Microbiol 65(2):359–366PubMedGoogle Scholar
- Wyss M, Pasamontes L, Friedlein A, Remy R, Tessier M, Kronenberger A, Middendorf A, Lehmann M, Schnoebelen L, Rothlisberger U, Kusznir E, Wahl G, Muller F, Lahm HW, Vogel K, van Loon AP (1999b) Biophysical characterization of fungal phytases (myo-inositol hexakisphosphate phosphohydrolases): catalytic properties. Appl Environ Microbiol 65:367–373PubMedGoogle Scholar