Powdery Mildew- and Salicylic Acid-Induced Gene Expression in Grapevine

Infection by the pathogen grape powdery mildew (Erysiphe necator) causes changes in the transcriptome of its susceptible host Vitis vinifera. Infection triggers the host to synthesize the signaling molecule salicylic acid (SA) which regulates the expression of a broad range of defense-related plant genes. In addition, it is hypothesized that E. necator directly modulates gene expression in V. vinifera via the haustorial complex. This microarray experiment was designed to dissect host transcriptome changes triggered directly by E. necator infection and indirectly through the SA response. We accomplished this by conducting two separate global leaf transcriptome analyses using the Vitis Affymetrix GeneChip platform: in one, we compared the leaves with fully established PM colonies to healthy reference leaves, in another, we compared healthy leaves with artificially elevated SA levels to healthy reference leaves. Overlaying host transcriptome changes from these two experiments enabled us to glean out V. vinifera genes that modulate their expression in response E. necator in an SA-independent manner.

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