title: Codon-modifications and an endoplasmic reticulum-targeting sequence additively enhance expression of an Aspergillus phytase gene in transgenic canola.
abstract: Transgenic plants offer advantages for biomolecule production because plants can be grown on a large scale and the recombinant macromolecules can be easily harvested and extracted. We introduced an Aspergillus phytase gene into canola (Brassica napus) (line 9412 with low erucic acid and low glucosinolates) by Agrobacterium-mediated transformation. Phytase expression in transgenic plant was enhanced with a synthetic phytase gene according to the Brassica codon usage and an endoplasmic reticulum (ER) retention signal KDEL that confers an ER accumulation of the recombinant phytase. Secretion of the phytase to the extracellular fluid was also established by the use of the tobacco PR-S signal peptide. Phytase accumulation in mature seed accounted for 2.6% of the total soluble proteins. The enzyme can be glycosylated in the seeds of transgenic plants and retain a high stability during storage. These results suggest a commercial feasibility of producing a stable recombinant phytase in canola at a high level for animal feed supplement and for reducing phosphorus eutrophication problems.
authors.affiliation: Shanghai Key Laboratory of Agricultural Genetics and Breeding, Agro-Biotechnology Research Center, Shanghai Academy of Agricultural Sciences, Shanghai, People's Republic China.
authors.forename: Ri-He
authors.initials: RH
authors.lastname: Peng
authors.forename: Quan-Hong
authors.initials: QH
authors.lastname: Yao
authors.forename: Ai-Sheng
authors.initials: AS
authors.lastname: Xiong
authors.forename: Zong-Ming
authors.initials: ZM
authors.lastname: Cheng
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
mesh_terms: D010832:6-Phytase / Q000235:genetics* / Q000378:metabolism*; D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001230:Aspergillus / Q000201:enzymology* / Q000235:genetics*; D029688:Brassica napus / Q000235:genetics* / Q000378:metabolism; D002645:Chickens / Q000254:growth & development; D003062:Codon / Q000235:genetics*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D005818:Genetic Engineering / Q000379:methods*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D012639:Seeds / Q000235:genetics / Q000378:metabolism
chemical_list: D003062:Codon; D010832:6-Phytase