Abstract 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 SPEXGENO 2010 高通量组织研磨机
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