GM Maize Expressing a Fungal Phytase Gene

Phytic acid, a chemical largely contained in cereal grains, has a negative impact on animal nutrition and the environment. Phosphorus in maize seeds exists as phytate, which is unavailable to monogastric animals because they lack the enzyme phytase needed for its digestion. Inorganic phosphate is therefore being added to the otherwise phosphorus rich seeds. Phytic acid is also known to form complexes with metal ions like iron, zinc, magnesium and potassium, preventing the absorption of these minerals by animals. In addition, the undigested phytic acid excreted in animal wastes is considered as the leading source of phosphorus pollution from agriculture.

By introducing the gene phyA2 from the fungus Aspergillus, researchers from the Chinese Academy of Agricultural Sciences obtained transgenic maize lines stably expressing the enzyme phytase. Phytase activity in GM maize seeds reached a 50-fold increase compared to their non-transgenic counterparts. The agronomic properties of the GM maize lines were not affected and phytase expression was found to be stable for four generations. The phytase expression lines can be used for further development of new maize hybrids with improved phosphorus availability.

Read the full paper published by Transgenic Research at http://www.springerlink.com/content/ju8241521771j394/fulltext.pdf or read the abstract at http://www.springerlink.com/content/ju8241521771j394/?p=6a8ab7085bd344d0a3e4d3792ce2655e&pi=2