ARS | Publication request: Functional genomic analysis of apple (Malus) EST's associated with fire blight (Erwinia amylovora)

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 27, 2007
Publication Date: July 1, 2007
Citation: Norelli, J.L., Borejsza-Wysocka, E., Baldo, A.M., Aldwinckle, H.S., Bassett, C.L., Farrell, R.E., Malnoy, M., Lalli, D., Korban, S.S., Gasic, K., Wisniewski, M.E. 2007. Functional genomic analysis of apple (Malus) EST's associated with fire blight (Erwinia amylovora). Phytopathology. 97:5185.

Technical Abstract: The goal of this project is to use a functional genomic analysis to characterize the response of apple to fire blight disease and thereby, identify new opportunities for improving fire blight resistance. Expressed sequence tags (ESTs) are derived from the mRNA isolated from a tissue and provide a crude "inventory" of the genes that are being expressed in that tissue. Bioinformatics was used to identify publicly available apple ESTs uniquely associated with Erwinia amylovora infected apple or similar to Arabidopsis ESTs associated with Pseudomonas syringae pv. tomato infection. Currently, RNA induced (RNAi) gene silencing is being used to elucidate the possible role of 19 candidate apple ESTs in fire blight resistance and susceptibility. To select apple RNAi mutants, an efficient high-throughput system of transformation for apple was developed in which only one EST-silencing gene was inserted per transgenic line. The system uses a multi-vector transformation approach and PCR primers developed for pHellsgate8-derived vectors that can: 1) detect the presence of single or multiple EST silencing insertions in the RNAi transgenic and 2) provide sequencing template to determine the EST contained in silencing insertion. Additional candidate ESTs are currently being selected based upon ongoing cDNA suppression subtractive hybridization and cDNA-AFLP analyses.