Data from: Pleiotropic effect of the Flowering Locus C on plant resistance and defence against insect herbivores

1. Plants vary widely in the extent to which they defend themselves against herbivores. Because the resources available to plants are often site-specific, variation among sites dictates investment into defence, and may reveal a growth-defence trade-off. Moreover, plants that have evolved different life-history strategies in different environments may situate themselves on this trade-off curve differently. For instance, plants that flower later have a longer vegetative lifespan, and may accordingly defend themselves differently than those that flower earlier. 2. Here, we tested whether late-flowering plants, with a longer vegetative lifespan, invest more in defence than early-flowering plants, using recombinant genotypes of the annual herb Cardamine hirsuta that differ in flowering time as a result of differences in the activity of the major floral repressor Flowering Locus C (FLC). 3. We found that variation at FLC was mainly responsible for regulating flowering time and allocation to reproduction, but this partially depended on where the plants grew. We also found that variation at FLC mediated plant allocation to defence, with late-flowering plants producing higher levels of total glucosinolates and stress-related phytohormones. Nonetheless, plant growth and the qualitative values of plant defence and plant resistance against specialist herbivores were mainly independent from FLC. 4. Synthesis - Our results highlight pleiotropic effects associated with flowering-time genes that might influence plant defence and plant-herbivore interactions.

1. 植物抵御植食性昆虫的防御强度存在广泛差异。由于植物可获取的资源往往具有生境特异性，生境间的资源差异决定了植物的防御投入，这可能揭示生长-防御权衡（growth-defence trade-off）现象。此外，在不同环境中演化出不同生活史策略的植物，在该权衡曲线上的位置也会有所差异。例如，开花较晚的植物拥有更长的营养生长期，其防御策略也可能与开花较早的植物截然不同。
2. 本研究以开花时间受主要开花抑制基因Flowering Locus C（FLC）活性差异调控的一年生草本碎米荠（Cardamine hirsuta）的重组基因型为实验材料，旨在探究拥有更长营养生长期的晚开花植物是否比早开花植物投入更多防御资源。
3. 研究结果显示，FLC位点的变异主要调控植物的开花时间与繁殖分配，但这一调控作用在一定程度上依赖于植物的生长生境。同时，FLC位点的变异介导了植物的防御资源分配：晚开花植物的总硫代葡萄糖苷（glucosinolates）与胁迫相关植物激素（phytohormones）水平显著更高。不过，植物生长、防御性状的质化特征以及对专食性植食昆虫的抗性，主要与FLC位点变异无关。
4. 综合分析——本研究结果凸显了与开花时间基因相关的多效性（pleiotropic effects）效应，这类效应可能会影响植物防御以及植物-植食昆虫间的互作关系。