| Abstract Detail
Protein Targeting and Vesicular Trafficking Winslow, Stephanie [1], Miles, Stacy [1], Nelson, Andrea [1], Betts, Scott [2]. Consistent and high expression of an E. coli derived phytase in three consecutive generations of transgenic maize seed. Phytase is widely used as a feed supplement in monogastric animal diets to increase the digestibility of phytate-bound phosphorus and to reduce the requirement for inorganic phosphate. Feed phytases currently on the market in the US are all produced by microbial fermentation and formulated as dry or liquid concentrates. Alternatively, the enzyme may be expressed directly in a feed ingredient such as corn. In an effort to demonstrate the feasibility of this approach, we have investigated the expression of an E. coli-derived phytase in three consecutive generations of transgenic corn homozygous for one or two TDNA insertions (integration events). The gene products of the two high-expressing events were targeted to different subcellular compartments. Seed hemizygous for both events were generated. The resulting double hemizygous plants were then selfed to generate a population of seed segregating both transgenic events. Seed from three consecutive generations of selfed plants homozygous for one event or the double event stack were measured for recombinant phytase activity. Here we report that extractable phytase levels in seed from consecutive generations of selfed plants tended to be consistent and high but also varied by as much as two-fold. Seed homozygous for the double event stack accumulated phytase activity to levels higher than those measured in seed containing only a single event. In the last generation analyzed, the average phytase level in seed from three plants containing the double event stack were 6.2mg with a range of 5.4mg to 7.0mg recombinant phytase per gram seed. To our knowledge this is the highest level of recombinant protein reported for whole maize kernels.
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1 - Syngenta Biotechnology, RTP NC
2 - Syngenta Biotechnology, RTP NC, 3054 E. Cornwallis RD, Research Triangle Park, NC, 27709, USA
Keywords:
protein expression in maize
enzymes
protein expression in maize seed.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P22010
Abstract ID:296 |
