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 Pseudomon...

金属超富集植物（metal hyperaccumulator）天蓝遏蓝菜（N. caerulescens）可利用金属作为抵御病原菌的防御手段。既往研究表明，金属与诱导型防御之间同时存在权衡效应与协同效应。天蓝遏蓝菜的不同种群在金属富集能力上存在显著差异。本研究旨在验证如下假说：种群间的富集能力差异会导致防御策略间的权衡产生不同结果。本研究选取4个天蓝遏蓝菜种群，比较其锌浓度、芥子油苷（glucosinolate）浓度以及包括活性氧（ROS）和细胞死亡在内的诱导型应激反应，并将上述指标与植物病原菌丁香假单胞菌（Pseudomonas syringae）、该菌的锌耐受突变株，以及从天蓝遏蓝菜自然种群中分离得到的假单胞菌属（Pseudomonas）病原菌的生长情况进行关联分析。结果显示，不同种群的防御策略差异显著。当防御策略生效时，病原菌主要受到金属、细胞死亡或有机防御的限制；不同种群间，这些防御机制之间同时存在权衡与协同效应。此外，本研究发现有关假单胞菌（Pseudomon...）的证据。