TRANSCRIPTIONAL RESPONSE OF MALUS TO ERWINIA AMYLOVORA INFECTION

Suppression subtractive cDNA hybridization (SSH) was used to identify genes that are differentially up- and down-regulated in apples (Malus ×domestica) in response to challenge with Erwinia amylovora (Ea). cDNA libraries were constructed from E. amylovora– and mock-challenged ‘Gale Gala’ apple leaf tissue at various time intervals after challenge treatment, ranging from 1 to 72 hours post inoculation (hpi) and utilized in SSH. A total of 432 non-redundant Malus ESTs isolated by SSH in response to E. amylovora challenge were characterized by bioinformatic analysis.
Many ESTs identified following Ea-challenge of apple were similar to genes previously reported to respond to bacterial challenge in Arabidopsis thaliana. The results indicate that there was a substantial early (1 and 2 hpi) transcriptional response in apple to fire blight disease involving both the down- and up-regulation of host genes.
Additionally, genes identified responding to fire blight challenge early (1 and 2 hpi) differed from those identified later (24, 48, 72 hpi) in the infection process.
For example, within the defense/stress functional category, ESTs representing several different PR proteins were first detected 48 hpi (up-regulated), whereas earlier defense/stress ESTs were primarily associated with oxidative and osmotic stress.

XI International Workshop on Fire Blight

J.L. Norelli, C.L. Bassett, D.A. Lalli, R.E. Farrell, Jr., A.M. Baldo, H.S. Aldwinckle

apple, fire blight, Rosaceae, plant pathogenic bacteria, fruit tree diseases, Gala, suppression subtractive hybridization, expressed sequence tag, EST, gene regulation

https://doi.org/10.17660/ActaHortic.2008.793.26