Jasmonate, salicylate, and ethylene-responsive transcriptomics discovery in spikelets of three wheat genotypes reveals a rapid and conserved response for jasmonate signaling.

Abstract

The accumulation of plant hormones in different tissues leads to transcriptional reprogramming that guides the downstream phenotypic response. Current models are largely derived from Arabidopsis, and increasing evidence indicates that monocots only partially conform to these canonical pathways, with additional variability even within the clade. In cereals, salicylate (SA), jasmonate (JA), and ethylene (ET) signaling play important roles in both inflorescence development and pathogen defense. This communication focuses on the transcriptional responses of wheat inflorescence tissue in three genotypes 8 h following exogenous applications of salicylic acid (SA), methyl jasmonate (MeJA), and the ethylene-releasing compound, ethephon (ETp). Nearly 8000 differentially expressed genes (DEGs) were detected in response to MeJA, approximately half of which were conserved across all three genotypes. In contrast, SA and ETp elicited limited responses, each inducing fewer than 100 DEGs with little to no overlap among genotypes. The comparatively feeble response to SA and ETp suggests a delayed response compared to MeJA. Other studies have assessed differential transcriptomes at 24 h or later. Notably, other studies in cereals, including wheat, have also reported less pronounced transcriptional changes to salicylate and ethylene signaling. These findings demonstrate both conservation and genotype-specific variation in the transcriptional response to plant hormones.