Transcriptome analysis of tomato in response to treatment with neutralized phosphorous acid (NPA)

Phosphonate related fungicides such as neutralized phosphorous acid (NPA) are effective for the control of plant diseases, especially those caused by Phytophthora and other oomycetes. It has been suggested that phosphonate may induce plant resistance, however, the mechanism is not clear thus far. We performed microarray analysis using Affymetrix Tomato Genome Array to identify tomato genes that are differentially expressed in response to NPA treatment. At 6 and 12 hours post treatment (hpt) of the tomato plants with NPA or water (ddH2O, as the control), total RNAs were isolated from leaves and subjected to microarray analysis by the use of Affymetrix Tomato Genome Array. To reduce the biological variability, each hybridization experiment was performed with RNA prepared from pools of five plants. The total set of experiments was repeated twice.