Data from: Variation in defence strategies in the metal hyperaccumulator Noccaea caerulescens is indicative of synergies and trade-offs between forms of defence

The metal hyperaccumulator, N. caerulescens, uses metals as a defence against pathogens. Earlier work has suggested both trade-offs and synergies between metals and inducible defences. Different populations of N. caerulescens vary in metal accumulation. Here, we test the hypothesis that this produces different outcomes in trade-offs between defences. We compare zinc concentrations, glucosinolate concentrations, and inducible stress responses, including ROS and cell death, in four N. caerulescens populations, and relate these to the growth of the plant pathogen Pseudomonas syringae, its zinc tolerance mutants, and Pseudomonas pathogens isolated from a natural population of N. caerulescens. The populations display strikingly different defences. Where defences are successful, pathogens are limited primarily by metals, cell death, or organic defences, with evidence of both trade-offs and synergies between these, depending upon population. In addition, we find evidence that Pseudomonas pathogens may evolve to overcome any of these strategies, indicating that the arms race continues. These data indicate that defensive enhancement, joint effects and trade-offs between forms of defence are all plausible explanations for the evolution of metal-based defences, with factors including metal availability and pressures from metal-tolerant pathogens likely shaping the current strategy of each ecotype