Plant Molecular Biology

, 67:347

The sweet potato sporamin promoter confers high-level phytase expression and improves organic phosphorus acquisition and tuber yield of transgenic potato


  • Ya-Fang Hong
    • Graduate Institute of Life SciencesNational Defence University
    • Institute of Molecular BiologyAcademia Sinica
  • Chang-Yeu Liu
    • Division of Applied BiologyAnimal Technology Institute Taiwan
  • Kuo-Joan Cheng
    • Agricultural Biotechnology Research CenterAcademia Sinica
  • Ai-Ling Hour
    • Department of Life ScienceFu Jen Catholic University
  • Min-Tsair Chan
    • Agricultural Biotechnology Research CenterAcademia Sinica
  • Tung-Hai Tseng
    • Division of BiotechnologyTaiwan Agricultural Research Institute
  • Kai-Yi Chen
    • Department of AgronomyNational Taiwan University
  • Jei-Fu Shaw
    • Institute of Plant and Microbial SciencesAcademia Sinica
    • Institute of Molecular BiologyAcademia Sinica

DOI: 10.1007/s11103-008-9324-6

Cite this article as:
Hong, Y., Liu, C., Cheng, K. et al. Plant Mol Biol (2008) 67: 347. doi:10.1007/s11103-008-9324-6


The sweet potato sporamin promoter was used to control the expression in transgenic potato of the E. coli appA gene, which encodes a bifunctional enzyme exhibiting both acid phosphatase and phytase activities. The sporamin promoter was highly active in leaves, stems and different size tubers of transgenic potato, with levels of phytase expression ranging from 3.8 to 7.4% of total soluble proteins. Phytase expression levels in transgenic potato tubers were stable over several cycles of propagation. Field tests showed that tuber size, number and yield increased in transgenic potato. Improved phosphorus (P) acquisition when phytate was provided as a sole P source and enhanced microtuber formation in cultured transgenic potato seedlings when phytate was provided as an additional P source were observed, which may account for the increase in leaf chloroplast accumulation (important for photosynthesis) and tuber yield of field-grown transgenic potato supplemented with organic fertilizers. Animal feeding tests indicated that the potato-produced phytase supplement was as effective as a commercially available microbial phytase in increasing the availability of phytate-P to weanling pigs. This study demonstrates that the sporamin promoter can effectively direct high-level recombinant protein expression in potato tubers. Moreover, overexpression of phytase in transgenic potato not only offers an ideal feed additive for improving phytate-P digestibility in monogastric animals but also improves tuber yield, enhances P acquisition from organic fertilizers, and has a potential for phytoremediation.


Sporamin promoterPhytasePotatoSweet potatoFeed additiveTuber yield and size

Supplementary material

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Copyright information

© Springer Science+Business Media B.V. 2008