Crop domestication reduces root volatile organic compounds diversity and abundance across species

Abstract 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 (CWRs), 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, broad bean, cucumber, sunflower and tomato), comparing landraces and CWRs. 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 CWRs. Total net depletion of VOCs was also reduced in domesticates. Chemical composition was more dependent on crop identity than on domestication status, although for broad bean and barley an effect of the latter was seen. VOC diversity was negatively related to bacterial diversity, and VOC profiles explained bacterial and part of fungal 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.