Transcriptional response of Arabidopsis thaliana to exogenous application of pipecolic acid

We have previously shown that the resistance increase observed after biological systemic acquired resistance (SAR) induction in plants can be mimicked by exogenous plant treatment with (pipecolic acid) Pip (Návarová et al., 2012; Bernsdorff et al., 2016). In order to investigate whether elevations of Pip are sufficient for a SAR-like transcriptional reprogramming in leaf tissue, we supplied individual Arabidopsis Col-0 and fmo1 mutant plants with doses of 10 µmol Pip and determined the transcriptional response in leaves one day later on the whole genome level by RNA-sequencing analyses in relation to untreated plants. Arabidopsis thaliana plants were grown individually in pots containing a mixture of soil, vermiculite and sand (8:1:1) in a controlled cultivation chamber with a 10-h day (9 AM to 7 PM; photon flux density 100 mol m-2 s-1) / 14-h night cycle and a relative humidity of 70 %. Day and night temperatures were set to 21°C and 18°C, respectively. Experiments were performed with 5- to 6-week-old, naive plants exhibiting a uniform appearance.Treatments with Pip were essentially performed as detailed in Návarová et al. (2012).10 ml of a 1 mM aqueous solution of Pip (equates to 10 µmol) were pipetted onto the soil of individually cultivated plants. 10 ml of water were applied in the control treatments. Three biologically independent, replicate experiments were performed. In each experiment, at least 4 full-grown leaves from 6 different plants were pooled 24 hours after the treatment with Pip or water for one biological replicate. In this way, 3 biologically independent, replicate samples per treatment and plant genotype were obtained.