ARS | Publication request: Rapid Genome Response of Malus to Infection by Erwinia amylovora

Submitted to: Gordon Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2006
Publication Date: N/A

Technical Abstract: Fire blight, caused by the bacterium Erwinia amylovora, is a destructive disease of apple, pear, and other plants in the subfamily Maloideae of the Rosaceae. The goal of this study was to use a global analysis of gene expression to characterize the temporal response of apple to infection by E. amylovora. cDNA subtractive hybridization was used to compare the populations of mRNA in mock inoculated (buffer controls) and E. amylovora inoculated "Gala" apple leaves at time intervals after challenge and to obtain EST clones. By subtracting cDNA synthesized from mRNAs expressed in one state (mock inoculated) from cDNAs derived from mRNAs expressed in another state (fire blight challenged) one can obtain sequences that are modulated when comparing the two mRNA populations side-by-side because sequences common to both populations are removed by hybridization. Gel electrophoresis of PCR-amplified subtracted cDNAs and unsubtracted controls indicate a greater quantity and size diversity in reverse subtracted samples (down-regulated ESTs) collected at 1h and 2h in comparison to forward subtracted samples (up-regulated) at 1h, 2h, 12h, pooled early samples (15 min, 1 h, 2h, 6h, 12h, 24h), and pooled later samples (48h, 72h), or in comparison to reverse subtracted samples (down-regulated) at 24h and 48h. PCR amplified subtracted cDNAs were cloned, sequenced, and identified by BLAST analysis.