Allelic composition and genetic background effects on transgene expression and inheritance in white clover

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• 作者：Alicia Scott ; Derek Woodfield and Derek W.R. White
• 关键词：breeding strategy ; gene dosage ; genetic background ; inheritance ; transgene expression ; transgenic white clover
• 刊名：Molecular Breeding
• 出版年：1998
• 出版时间：December 1998
• 年：1998
• 卷：4
• 期：6
• 页码：479-490
• 全文大小：113 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

Allelic composition and genetic background effects on GUS expression and inheritance using a chimeric (cauliflower mosaic virus 35Sp:uidA) transgene were investigated in white clover as a prelude to transgenic cultivar development. Stable expression and Mendelian inheritance of the uidA transgene was observed over two generations when the uidA transgene was maintained in a heterozygous state. Transgenic backcross progeny (BC1) were intercrossed to produce segregating F2 populations. GUS-positive F2 plants were test-crossed with a non-transgenic control plant to determine whether individuals were heterozygous or homozygous for the transgene. Both expected and distorted segregation ratios were observed. Distortion of the segregation ratio was not caused by transgene inactivation or rearrangement, but was influenced by genetic background. BC1, BC2 and F2 populations were found to have similar levels of uidA gene expression. Quantification of GUS expression from progeny of high and low GUS expressing plants indicate that it is possible to alter transgene expression through selection. No difference was found between the level of expression for F2 plants homozygous or heterozygous for the transgene. These results indicate that F2 plants, homozygous for a transgene, might be used to develop a transgenic cultivar. However, progeny testing to determine the influence of genetic background is a prerequisite to such a development.