Shifts in plant functional trait dynamics in relation to soil microbiome in modern and wild barley

Understanding domestication's impact on crop root traits and interactions with soil microbiomes is vital for improving crop resilience and agricultural sustainability. Using this knowledge to enhance root systems, reduce chemical inputs, and adapt crops to environmental stress will help to increase global food production, promote eco‐friendly farming, and mitigate the effects of climate change. Additionally, identifying microorganisms specific to plant species may help in biodiversity conservation. Advancing scientific understanding and educating future generations on the intricate relationships between plants, soil, and microorganisms is integral to developing innovative, sustainable agricultural practices and improved food security. Domestication and intensive management practices have significantly shaped characteristics of modern crops. However, our understanding of domestication's impact had mainly focused on aboveground plant traits, neglecting root and rhizospheric traits, as well as trait–trait interactions and root‐microbial interactions. To address this knowledge gap, we grew modern (Hordeum vulgare L. var. Barke) and wild barley (Hordeum spontaneum K. Koch var. spontaneum) in large rhizoboxes. We manipulated the soil microbiome by comparing disturbed (sterilized soil inoculum, DSM) versus non‐disturbed (non‐sterilized inoculum, NSM) microbiome. Results showed that modern barley grew faster and increased organic‐carbon exudation (OCEXU) compared to wild barley. Both barley species exhibited accelerated root growth and enhanced OCEXU under DSM, indicating their ability to partially compensate and exploit the soil resources independently of microbes if need be. Plant trait network analysis revealed that modern barley had a denser, larger, and less modular network of microbes than wild barley indicating domestication's impact on trait–trait coordination. In addition, the relative abundance of bacteria did not vary between wild and modern barley rhizospheres; however, species‐specific unique bacteria were identified, with stronger effects under DSM. Overall, our findings highlight domestication‐driven shifts in root traits, trait coordination, and their modulation by the soil microbiome.