Methyl jasmonate seed treatment mitigates the defense-growth trade-off and tailors plant response to specific pests
Seed defence priming is emerging as a novel, cost-efficient and environmentally safe tool for pest management. Previous reports suggest that this strategy could potentially uncouple the defence-growth trade-off in plants, but this role and the mechanisms underlying it remain elusive. Here, we investigated the ability of seed priming with four phytohormones and two plant vitamins to uncouple the growth-defence trade-off in Arabidopsis thaliana upon pest infestation, focusing on its molecular dynamics. To broaden our scope, two phytophagous species from different feeding guilds were used: the generalist cell-content sucker Tetranychus urticae, and the specialist chewer Pieris brassicae. A combined -omics approach revealed distinct and interactive effects of seed priming and herbivory. Specifically, seed priming with 0.1 mM methyl jasmonate induced a state of readiness characterized by reduced stomatal aperture, high transcriptomic variation, increased sugar content and enhanced translational rate. Upon pest infestation, primed plants exhibited herbivore-specific responses. Interaction of seed priming and T. urticae infestation increased amino acid levels, hydroxycinnamic acid amide production, and reallocated resources from arabidopsides and anthocyanin biosynthetic pathways. In contrast, P. brassicae infestation in primed plants led to enhanced anthocyanin biosynthesis, alterations in lignin metabolic intermediates, and sustained carbon and nitrogen sources. These findings demonstrate that seed priming can enhance pest-specific defences in plants without incurring a fitness penalty, effectively managing infestations while maintaining growth. Overall design: RNA-seq profiling of methyl jasmonate-primed and non-primed plants under three infestation conditions (control, 24 hpi Tetranychus urticae and 24 hpi Pieris brassicae)