Fig. 4

Elicitation of early A. thaliana defence response genes by droplet depositing the bacterial peptide flg22: a As a milder stress stimulus than flg22 syringe infiltration we pipetted a 1 µl droplet of 500 nM flg22 and, as an internal control, water on the abaxial surface of a leaf. 1 h after droplet deposition we dissected a lateral section into 8 squares with square-1 and square-8 as leaf margins, square-3 as flg22 treated spot, square-6 as water treated spot and square-5 as midvein. Image b shows an overlay of the spatial expression patterns of the 63 FLARE genes characterised by Navarro et al. [18] present in our dataset. Each group is coloured separately, the average expression of each FLARE group is shown as the dashed line. Image c shows the spatial expression of all 523 detected DE genes grouped in three different clusters. From left to right: One cluster (1) contains genes which are lower expressed at the flg22 treatment area, two clusters contain genes with higher expression at the flg22 treatment spot in comparison to adjacent areas but with narrower (2) and broader (3) spatial expression. The yellow background in the plot indicates the flg22 treated area, the blue background indicates the water treated control area