Figure 1
Overview of transcriptome profile of Arabidopsis thaliana exposed to drought-recovery-pathogen treatment in comparison to drought recovery and pathogen treatments. A. thaliana was exposed to Pseudomonas syringae pv. tomato DC3000 (Pst DC3000; P) and combined drought-recovery-pathogen (DRP) treatments as outlined in Figure S1. Microarray hybridization on Affymetrix WT gene chip array was conducted using total RNA isolated from leaf samples (38-d-old plants) harvested at 24 hours post treatment (hpt). Differentially expressed genes (DEGs) in each stress treatment were identified in comparison to control conditions and threshold was set at change greater than 2 fold and ANOVA p value < 0.05. Differentially expressed genes under drought recovery (DR) were retrieved from Coolen et al.30. Venn diagram between DEGs in individual (DR and P) and combined (DRP) stress revealed the presence of transcripts exclusively under DRP stress and were regarded as ‘unique’ genes, and ‘common’ transcripts shared between individual and combined stresses (A). Expression profile of genes common among DR, P and DRP is presented in the form of heat map. Common transcripts were categorized as genes with similar expression pattern in all the three stress conditions and as genes with ‘tailored’ expression pattern under different stresses (up-regulated vs. down-regulated and vice versa) (B). Expression values were used to plot heat maps using GENE-E software (http://www.broadinstitute.org/cancer/software/GENE-E/). Colour bar scale shows the fold change range with a red and blue colour representing up- and down-regulation respectively. Corresponding gene names and descriptions for the gene IDs presented in the figure are provided in Supplementary File S1. Genes common to individual and combined stress and genes unique to the DRP stress were functionally categorized and represented based on gene ontology (GO) biological process (C).
