MeJA seed priming enhances pest resistance in Arabidopsis and Brassica through species-specific molecular mechanisms

Sustainable and cost-efficient alternatives to conventional pest management are needed. Seed priming, which enhances plants response to stress, offers a promising solution. We previously demonstrated that seed priming with methyl jasmonate (MeJA) or salicylic acid (SA) increases resistance to pests without growth penalties in Arabidopsis thaliana. Here, we investigate whether these benefits extend to the crop Brassica rapa and whether underlying mechanisms are conserved. In both plant species, MeJA and SA enhanced resistance to the generalist mite Tetranychus urticae and the specialist caterpillar Pieris brassicae, without compromising growth. Based on its comparatively greater effects, MeJA was selected for molecular analyses. Transcriptomic and metabolomic profiling revealed conserved co-expression networks but limited overlap in specific genes and metabolites. Additionally, the magnitude and direction of MeJA priming varied with both plant and herbivore species, revealing strong plant-pest interaction effects. In B. rapa, seed priming promoted SA accumulation under mite infestation and glucosinolate pathway activation under caterpillar feeding. Overall, we observed that phenotypic benefits were broadly conserved across Brassicaceae, but its molecular bases were shaped by plant species and pest identity, as well as context-specific interactions. This comparative study underscores the potential of tailoring priming strategies to crop species for sustainable pest management.