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United States Department of Agriculture

Agricultural Research Service

Research Project: USING FUNCTIONAL AND APPLIED GENOMICS TO IMPROVE STRESS AND DISEASE RESISTANCE IN FRUIT TREES Title: Long-term stability of attacin E expression in transformed apple after 12 years in the field and effect of the expression of this gene on the fruit characteristics

Authors
item Norelli, John (jay)
item Malnoy, Mickael -
item Borejsza-Wysocka, Ewa -
item Aldwinckle, Herb -

Submitted to: BioMed Central (BMC)Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 3, 2010
Publication Date: June 3, 2010
Citation: Norelli, J.L., Malnoy, M., Borejsza-Wysocka, E., Aldwinckle, H.S. 2010. Long-term stability of attacin E expression in transformed apple after 12 years in the field and effect of the expression of this gene on the fruit characteristics. BioMed Central (BMC)Biotechnology. DOI: 10.1186/1472-6750-10-41.

Interpretive Summary: The future use and commercialization of genetically engineered fruit trees depends upon thorough evaluation of the potential environmental and public health impact of the modified plants, the stability of the introduced gene over a prolonged period of time and the effect of the gene on tree and fruit characteristics. This paper reports a 12 year study of the stability of the lytic protein gene, attacin E, in the apple cultivar ‘Galaxy’ and its effect on resistance to fire blight disease. Molecular tests indicated that the number of copies of the gene and its expression was stable in the leaves and fruit in several independently transformed lines. Similarly, the effects of the attacin E on enhanced fire blight resistance were stable over the 12 year period. Silencing of the introduced gene was not observed. Also, the expression of this gene did not affect fruit shape, size, acidity, firmness, weight and sugar level, tree morphology, leaf shape or flower morphology or color compared to the control. Overall, the results suggest that genes introduced into fruit trees by genetic engineering will remain stable in both time and space, over extended periods and in different organs.

Technical Abstract: Transgenic trees currently are being produced by Agrobacterium-mediated transformation and biolistics. The future use of transformed trees on a commercial basis depends upon thorough evaluation of the potential environmental and public health impact of the modified plants, transgene stability over a prolonged period of time and the effect of the gene on tree and fruit characteristics. We studied the stability of expression and the effect on resistance to the fire blight disease of the lytic peptide gene, attacin E, in the apple cultivar Galaxy grown in the field for 12 years. Using Western blot and Southern analysis, we compared transgene copy number and observed stability of expression of this gene in the leaves and fruit in several transformed lines. No silenced transgenic plant was detected. Overall, these results suggest that transgene expression in perennial species, such as fruit trees, remains stable in time and space, over extended periods and in different organs. Also, the expression of this gene does not affect fruit shape, size, acidity, firmness, weight and sugar level, tree morphology, leaf shape or flower morphology or color compared to the control.

Last Modified: 10/25/2014
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