N-hydroxy-pipecolic acid mediated priming of salicylic acid signalling in Arabidopsis thaliana

N-hydroxy-pipecolic acid (NHP) primes Aarabidopsis thaliana to confer faster and stronger activation of immune responses, but how NHP interacts with other immune-inducing phytohormones is unknown. Here we investigated the crosstalk between priming phytohormone NHP and immune inducing phytohormone salicylic acid (SA). We show that pretreatment with NHP modulates the SA-inducible transcriptome, wherein some SA-expressed genes show enhanced SA-sensitivity and some show reduced SA-sensitivity. 12 day old wild type (col-0) seedlings grown on MS media were treated with 1mM NHP or water overnight, then 0.5mM SA or water for 6 hours by immersion in 10ml of the respective chemicals. ~50 seedlings were pooled into one biological repeat, with three biological repeats total for this experiment. Seedlings were patted dry with tissue paper and frozen in liquid nitrogen for RNA extraction.