Figure 4.

NHP upregulates a battery of plant defense-related genes involved in distinct immune layers. Selected expression data of the RNA-seq analysis is illustrated. A, Genes involved in the biosynthesis and metabolism of SA and NHP, and in the regulation of the respective immune pathways. B, Genes implicated in hypersensitive cell death, cell-wall-based defense, and nonhost resistance. C, Genes involved in the biosynthesis of the Arabidopsis phytoalexin camalexin (Mucha et al., 2019). Genes significantly upregulated in the Col-0 wild-type upon NHP treatment (FDR < 0.05) are highlighted in color, genes not differentially regulated are depicted in grey. The heat map indicates the fold-changes of gene transcript levels (i.e. the ratios of the mean expression values of NHP versus control samples). Please note that all of the SA and NHP biosynthetic genes are invariably induced by NHP at the transcriptional level, whereas camalexin biosynthesis is only partially activated.