It is increasingly recognized that plant-soil feedbacks influence the composition and functioning of natural communities and ecosystems. However, our capacity to predict the outcome of such above-belowground interactions is still hampered by poor generalization capacity. As plant traits have been used to explain patterns in both plant and soil communities, they could provide a useful approach for explaining and predicting plant-soil feedback. Here, I will use the recent advances made in plant trait research, which have greatly increased our capacity to predict the responses of natural plant communities to environmental changes, to improve our mechanistic understanding of the factors underlying plant-soil feedback strength and sign (negative, neutral and positive) under changing environmental conditions. Based on the growth versus defence trade-off hypothesis, fast-growing plant species with acquisitive traits build up negative feedback, whereas slow-growing species with conservative traits develop positive feedback with their own soil biota. The growth-defence framework is widely based on leaf spectrum economy, and it is unknown how well predictive aboveground traits are for growth strategies of plant roots<br/>belowground. With my proposed project PLECTRA, I aim to investigate how well the sign and strength of plant-soil feedback can be predicted from aboveground and belowground plant traits. This knowledge will improve our understanding of the role that plant-soil feedback plays in structuring plant communities and will, among others, be helpful to enhance restoration success of degraded ecosystems and improve management of invasive species.