|WANG, MING LI|
Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/31/2003
Publication Date: 1/9/2004
Citation: Albert, H.H., Wang, M., Goldstein, C., Lemaux, P., Yu, X., Moore, P.H. 2004. Does single-copy transgene introduction reduce the frequency of PTGS in sugarcane? Plant, Animal and Microbe Genome Conference XII Proceedings. W125, p. 36.
Technical Abstract: Sugarcane undergoes post-transcriptional gene silencing at high frequency , and this constitutes a major barrier to both research and application of biotechnology. While it is known that single-copy transgenes can undergo gene silencing, high transgene copy numbers and complex integration patterns, which commonly occur as a result of gene gun bombardment, often correlate with high frequencies of transgene silencing. We are evaluating multiple approaches for the introduction of single- or low-copy transgenes, to determine if these methods can reduce transgene silencing. These methods include the use of insert-only DNA for bombardment , Cre/lox site-specific recombination to resolve multiple transgene copies , and the Ac/Ds transposon system to direct transgene integration by transposition . The use of linear expression cassette only DNA was determined in rice to produce a high frequency of low copy transgene insertions, with no evidence of silencing through the R4 generation . In contrast, in sugarcane we observed most transgenic lines produced by this method contained multiple transgene copies, with only three of 27 selected plants containing three or fewer copies. Accumulation of GMCSF in the low copy lines was not higher than multi-copy lines. Sugarcane lines produced by the other gene introduction methods are undergoing selection.