Poster: Posttranscriptional Regulation

Abs # 1085: Transgene silencing during vegetative propagation in grass plants

Presenter:	Dong, Shujie , sdong@unity.ncsu.edu
Authors	Dong, Shujie  (A)   Sivamani, Elumalai  (A)   Bai, Yuyu  (A)   Qu, Rongda  (A)
Affiliations:	(A): Department of Crop Science, North Carolina State University

Tall fescue, an important turfgrass and forage grass, was transformed with the herbicide resistant bar gene. Among three such transgenic plants, for the first few months, all the tillers of these plants, were resistant to application of 0.2-1% of the herbicide Finale (a commercial brand of herbicide containing 11% glufosinate). During vegetative propagation, two transgenic plants maintain resistance to Finale in all their tillers whereas the third plant (No 72) started showing segregation among the tillers in Finale resistance: some of which still maintain complete resistance, some of which showed partial resistance, and others lost the resistance completely. PCR analysis showed all the tillers tested contained the bar gene, while Northern hybridization indicated reduced steady state of bar gene mRNA in the susceptible tillers. All the preliminary data suggested transgene silencing occurred during tiller formation. We are very interested in this new type of transgene silencing in monocot plants and will provide more data in the poster.