Expression of a sulfur-rich maize seed storage protein, d-zein, in white clover (shape Trifolium repens) to improve forage quality

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• 作者：Shashi B. Sharma ; Kerrie R. Hancock ; Paul M. Ealing and Derek W.R. White
• 关键词：forage quality ; HA epitope ; seed storage protein ; transgenic white clover ; zein
• 刊名：Molecular Breeding
• 出版年：1998
• 出版时间：October 1998
• 年：1998
• 卷：4
• 期：5
• 页码：435-448
• 全文大小：123 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Plant Sciences
  
• 出版者：Springer Netherlands
• ISSN：1572-9788

文摘

A modified gene encoding a sulfur-rich maize seed storage protein, -zein, was introduced into white clover plants by Agrobacterium-mediated transformation. Expression of the gene was under the control of the double 35S promoter of cauliflower mosaic virus and the nopaline synthase gene transcription terminator. All of the transgenic plants expressing transgene-specific mRNA also accumulated -zein in their leaves. Levels of the HA epitope tagged -zein in the first fully expanded young leaves of different transgenic plants varied from 0.06 to 0.3% of total water-soluble protein. Expression of the protein was also detected in petioles, nodes, internodes, roots and seeds of the transgenic plants. N-terminal sequencing of the modified -zein from transgenic plants revealed that the protein is processed in white clover leaves as in maize seeds. All the transgenic plants expressing the -zein showed monogenic inheritance of the linked nptII gene conferring kanamycin resistance. The epitope tagged -zein is relatively stable in white clover leaves and in the highest expressing plants, its accumulation increased with increasing leaf age from 0.3 (youngest leaves) to 1.3% (oldest leaves) of total water-soluble protein. These results open up the possibility of using sulfur-rich and rumen-protected -zein to improve white clover forage quality.