Light intensity drives the antibiotic resistome in plant-soil systems through plant-microbe molecular-metabolic...

The threat of antibiotic resistance genes (ARGs) in agriculture to human health has garnered widespread attention. However, as a pivotal agronomic practice for crop management, the impact of light intensity on the dynamics of antibiotic resistome remains poorly understood, creating critical knowledge gaps in understanding ARGs fate and assessing dissemination risks in plant-soil systems. This study systematically investigated the effects of different light intensities (low, moderate, and high) on ARGs profiles in plant-soil systems and underlying mechanisms. High-throughput qPCR analysis demonstrated that variations in light intensity significantly altered the antibiotic resistome in the rhizosphere and leaf endosphere. Mechanistic investigations revealed that high light intensity suppressed the proliferation of ARGs by influencing metabolic and signaling networks in plant-microbe interactions, including regulating phytohormone levels, reactive oxygen species (ROS) production, quorum sensing (QS), two-component systems (TCS), and ATP-dependent metabolic activities. These molecular signals and metabolic activities inhibited antibiotic-resistant bacteria (e.g., Unclassified_f_Enterobacteriaceae) and pathogens (e.g., Paenarthrobacter) in the leaf endosphere, thereby reducing ARGs dissemination and the associated health risks from consumption. This study highlights the significant role of light intensities in influencing antibiotic resistome in plant-soil systems and provides a theoretical basis for developing photoregulation-based strategies to inhibit ARGs dissemination in agriculture.