Crop domestication has increased phosphorus-acquisition capacity but restricted root plasticity under phosphorus-limited conditions

Abstract

Crop domestication marks a crucial milestone in human civilization, yet our understanding of the changes in belowground crop traits, specifically those associated with phosphorus (P)-acquisition strategies, during domestication remains limited. Ten crop species and their wild relatives were grown under both P-sufficient (40 mg P kg⁻¹) and P-deficient (nil-P added) conditions to compare the biomass, P content and P-acquisition strategies related to root morphological and physiological traits. Domesticated crops presented a lower specific root length and acid phosphatase activity but greater arbuscular mycorrhizal (AM) colonization, more root-secreted carboxylates per plant, and higher values for root morphological traits such as root length than their wild relatives. Domesticated crops showed a 79 % higher P content than their wild relatives under P-deficient conditions, associated with a greater root length, AM-colonization rate and root-secreted carboxylates per plant in domesticated crops. Domesticated crops displayed significantly greater plasticity (shown as response ratio) in AM colonization rate, but lower plasticity in specific root length, acid phosphatase activity, and amount of root-secreted carboxylates per plant than their wild relatives in response to low plant-available soil P concentrations. Crop domestication increased P-acquisition capacity by combining P-scavenging and P-mining strategies but largely restricted root plasticity, specifically in P-acquisition strategies. We confirmed trade-offs among P-scavenging strategies related to soil exploration and P-mining strategies related to root-secreted carboxylates. Our results highlight the domestication effects on crop P-acquisition strategies mediated by plant-soil interaction, providing insights to further improve crop P-acquisition efficiency.