|Norelli, John (jay) - Jay|
|Farrell, jr, Robert|
Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: 3/24/2009
Publication Date: 7/1/2009
Citation: Norelli, J.L., Gardiner, S.E., Malnoy, M., Aldwinckle, H.S., Farrell, Jr, R.E., Horner, M., Celton, J., Baldo, A.M., Bowatta, D.R., Carlisle, C., Lalli, D., Bus, V., Bassett, C.L., Wisniewski, M.E. 2009. Using functional genomics to identify molecular markers for fire blight resistance (Erwinia amylovora) in apple (Malus). Acta Horticulturae. 839:415-420. Interpretive Summary:
Technical Abstract: Fire blight, caused by Erwinia amylovora (Ea), is a destructive disease of apple (Malus), pear (Pyrus) and some woody ornamentals in the rose family (Rosaceae). The goal of this project is to use a functional genomics approach to develop tools to breed fire blight resistant apples. Six hundred fifty expressed sequence tags (ESTs) associated with fire blight were identified from Ea-challenged apple leaf tissue by suppression subtractive hybridization (SSH) and cDNA-AFLP analysis. ESTs were ranked for their potential impact on resistance based on bioinformatics and inferences drawn from model systems. Simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers derived from highly ranked fire blight-associated ESTs were mapped in a ‘M.9’ x ‘Robusta 5’ population in which a major QTL for fire blight resistance has been located on Linkage Group 03. Highly ranked fire blight-associated ESTs were mapped to this QTL, as well as to the positions corresponding to the location of at least two QTLs reported in other populations (Calenge et al. 2005, Khan et al. 2006). Markers for heat shock protein 90 (Hsp81-2), a secretory class III peroxidase and a serine/threonine-protein kinase mapped to the LG03 fire blight resistance QTL and reduced its size from 12cM to 4cM. Markers for a “putative disease resistance protein” (NCBI AY347778) and Skp1 (SCF-type E3 ubiquitin ligase) mapped to positions corresponding to the location of two known QTLs on LG07 and LG12, respectively (Calenge et al. 2005, Khan et al. 2006). To date, of 28 candidate fire blight resistance gene markers that have been mapped, 6 have co-located to or near known fire blight resistance QTLs. This research will facilitate new methods of marker-assisted selection to efficiently breed superior apple cultivars with fire blight resistance.