Climate warming affects antibiotic resistance genes (ARGs) in soil and the plant microbiome, including seed endophytes. Seeds act as vectors for ARG dissemination in the soil–plant system, but the impact of elevated CO₂ on seed resistomes remains poorly understood. Here, a free-air CO₂ enrichment system was used to examine the impact of elevated CO₂ on seed-associated ARGs and seed endophytic bacteria and fungi. Results indicated that elevated CO₂ levels significantly increased the relative abundance of seed ARGs and mobile genetic elements (MGEs), especially those related to beta-lactam resistance and MGEs. Increased CO₂ levels also influenced the composition of seed bacterial and fungal communities and the complexity of bacteria–fungi interactions. Fungi were more sensitive to changes in the CO₂ level than bacteria, with deterministic processes playing a greater role in fungal community assembly. Co-occurrence network analysis revealed a stronger correlation between fungi and ARGs compared to bacteria. The structure equation model (SEM) showed that elevated CO₂ directly influenced seed resistomes by altering bacterial composition and indirectly through bacteria–fungi interactions. Together, our work offers new insights into the effects of elevated CO₂ on antibiotic resistomes in the seed endosphere, highlighting their increased dissemination potential within soil–plant systems and the associated health risks in a changing environment.

中文翻译：

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升高的 CO2 增加了种子内生菌中的抗生素耐药组：来自自由空气 CO2 富集 （FACE） 实验的证据


气候变暖会影响土壤和植物微生物组（包括种子内生菌）中的抗生素抗性基因 （ARG）。种子是 ARG 在土壤-植物系统中传播的载体，但 CO₂ 升高对种子抗性组的影响仍然知之甚少。在这里，使用自由空气 CO₂ 富集系统来检查 CO₂ 升高对种子相关 ARG 和种子内生细菌和真菌的影响。结果表明，CO₂ 水平升高显着增加了种子 ARGs 和移动遗传元件 （MGE） 的相对丰度，尤其是与 β-内酰胺抗性和 MGEs 相关的那些。CO₂ 水平的增加还影响了种子细菌和真菌群落的组成以及细菌-真菌相互作用的复杂性。真菌比细菌对 CO₂ 水平的变化更敏感，确定性过程在真菌群落组装中起着更大的作用。共生网络分析显示，与细菌相比，真菌和 ARGs 之间的相关性更强。结构方程模型 （SEM） 显示，升高的 CO₂ 通过改变细菌组成直接影响种子抵抗组，并通过细菌-真菌相互作用间接影响种子抵抗组。总之，我们的工作为升高的 CO₂ 对种子内圈抗生素耐药组的影响提供了新的见解，突出了它们在土壤-植物系统中增加的传播潜力以及在不断变化的环境中相关的健康风险。