ARS | Publication request: STRATEGIES FOR OBTAINING FIRE BLIGHT RESISTANCE IN APPLE BY RDNA TECHNOLOGY

Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: October 14, 2005
Publication Date: March 1, 2007
Citation: Aldwinckle, H.S., Malnoy, M., Borejsza-Wysocka, E.E., Norelli, J.L., Beer, S.V., Yang He, S. 2007. Strategies for obtaining fire blight resistance in apple by rdna technology. Acta Horticulturae. 738:283-285.

Technical Abstract: The fire blight disease of apple (Malus X domestica), caused by the bacterium Erwinia amylovora, is difficult to manage on most cultivars because of their susceptibility and the paucity of effective control materials. Because of apple's heterozygosity, self-incompatibility, and long generation time, rDNA technology is more attractive than conventional breeding for the development of resistant cultivars with fruit of high quality. Previously, we showed the effectiveness of certain anti-microbial genes (attacin, lysozyme) at increasing fire blight resistance, but their animal origin put their acceptability to consumers and growers into serious question. Genes from E. amylovora (hrpN) and phages (lysozyme, depolymerase) also appear to be effective at increasing resistance. They are probably more acceptable than animal genes. Most acceptable to consumers and growers are likely to be alterations in the expression of native apple genes resulting in enhanced resistance. We were able to add a copy of the apple transcription facilitator gene, MpNPR1, to susceptible apple cultivars and obtain increased fire blight resistance. Also, we obtained some apple lines in which certain pathogen-protein receptor genes of apple, DIPM1-4, are partially silenced; these appear to have increased resistance to E. amylovora. Our preferred strategy is to alter the expression of native apple genes, use plant (preferably apple) promoters, without using antibiotic or herbicide resistance selectable marker genes, in order to facilitate approval by regulatory agencies, and acceptance by growers and consumers.