Expression data from Arabidopsis plants misexpressing AtMYB30 after Xanthomonas inoculation at early timepoints

Plant immune responses to pathogen attack involve various defense mechanisms and among them, the Hypersensitive Response (HR), a form of programmed cell death occurring at invasion sites. AtMYB30, a transcription factor acts as a positive regulator of a cell death pathway conditioning the HR. We show by microarray analyses of Arabidopsis plants misexpressing AtMYB30 that the genes encoding the four enzymes forming the acyl-coA elongase complex, responsible for very long chain fatty acids (VLCFA) biosynthesis, are putative targets. Keywords: Time course after inoculation with a Xanthomonas strain, Xcc147, in Arabidopsis wild-type plants and transgenic plants (AtMYB30 overexpressor (ox) and antisense (as) lines 18 samples are analyzed : Leaves of 4 week-old plants syringe-infiltrated with the Xcc147 strain (or not) were harvested. In experiment 1, we selected 4 timepoints : T0 (not inoculated), 90-105 min, 2-4 h and 6 h post inoculation in the wild-type line, and in a transgenic line overexpressing AtMYB30. Experiment 2 is a biological replicate of experiment 1 (except for 6 hpi). In experiment 3, we focused on the early timepoint 90-105 min to compare the wild-type line and an AtMYB30 antisense line. Experiment 4 is a biological replicate of experiment 3. Plant material was pooled when necessary, and frozen before RNA extraction and hybridization on Affymetrix ATH1 microarrays. As a screen for candidate target genes, we looked for genes, i) up-regulated in the wild-type line after inoculation with Xcc147 as compared to time T0 (not inoculated) , ii) over-expressed in the AtMYB30 overexpressor line compared to the wild-type, and iii) down-regulated in the AtMYB30 antisense line compared to the wild-type.