Domestication reduces root VOC abundance and diversity in crops with species specific effects

Background and aims Plant domestication has been a long coevolutionary process with humans, profoundly shaping plant chemical traits. Secondary metabolites involved in plant interactions, such as volatile organic compounds (VOCs), may have been reduced in domesticates compared with crop wild relatives (CWR), with possible effects on root-associated bacterial communities and crop resilience. However, the effects of domestication in root VOCs and the implications of such changes remain unknown. Methods We conducted a greenhouse experiment with eight crops (barley, beet, fava bean, cucumber, lentil, lettuce, sunflower and tomato), comparing landraces and CWR. Root VOCs were collected with SPME fibres and analysed by GC–MS; root-associated bacterial diversity was also characterized. Results Domesticated plants emitted almost three times less total root VOCs and had lower compound diversity than CWR. Effects on VOC uptake were crop-specific (reduction in barley, beet and tomato, but not generalized). Chemical composition was more dependent on crop identity than on domestication status. VOC diversity was negatively related to bacterial diversity, and VOC profiles explained bacterial composition. Conclusions In summary, domestication has reduced the quantity and diversity of root VOCs, potentially impairing chemical communication and response to soil biota; CWRs emerge as reservoirs of chemical and genetic traits essential for restoring crop resilience and sustainability.