【摘要】 为阐明外源抗生素抗性细菌暴露对植物生长及根内生菌和根际细菌群落结构的影响，运用平板培养计数和16S rRNA基因高通量测序技术，研究外源抗生素抗性细菌暴露对小麦苗根长度和芽长度的抑制作用，对根内生菌和根际细菌群落的影响以及外源抗生素抗性向根内生菌中的转移情况。结果表明：外源抗生素抗性细菌暴露会抑制小麦苗根和芽的生长，抑制率随着外源抗生素抗性细菌浓度的增加而升高。当外源抗生素抗性细菌浓度为×10~8 CFU/mL时，小麦苗根长度和芽长度抑制率分别高达68.83%和36.87%。在外源抗生素抗性细菌暴露期间，小麦苗根内生菌中的狭义梭菌属5(Clostridium＿sensu＿stricto＿5)含量激增，至暴露末期成为相对丰度最高（45.02%）的菌属；而β变形菌目（Betaproteobacteriales）则始终是根际细菌中最主要的菌目，且相对丰度持续升高。外源抗生素抗性根内生菌比例与根内生菌中的狭义梭菌属5(Clostridium＿sensu＿stricto＿5)、狭义梭菌属1(Clostridium＿sensu＿stricto＿1)、芽孢杆菌属（Bacillus）和类芽孢杆菌属（Paenibacillus）的相对丰度呈显著正相关（P<0.05）。综上，外源抗生素抗性细菌暴露不仅显著抑制小麦苗的生长，还会改变小麦苗根内生菌和根际细菌的群落结构。持续暴露后，外源抗生素抗性会转移至小麦苗根内生菌中，狭义梭菌等可能是ARGs在小麦苗根部的宿主菌。更多还原

【Abstract】 To elucidate the effects of exogenous antibiotic-resistant bacteria(ARB) exposure on wheat growth and associated bacterial community assembly, the inhibitory impacts of exogenous ARB on wheat seedling root and shoot length, shifts in root endophytic and rhizosphere bacterial communities, and the horizontal transfer of exogenous antibiotic resistance genes(ARGs) to indigenous endophytic bacteria were investigated using plate culture counting and 16S rRNA high-throughput sequencing. The results showed that exogenous ARB exposure significantly suppressed wheat seedling root and shoot growth, with inhibition rates increasing in an ARB concentration-dependent manner. At an exogenous ARB concentration of 10~8 CFU/mL, the inhibition rates of seedling root and shoot length reached 68.83% and 36.87%, respectively. During the period of ARB exposure, the relative abundance of Clostridium＿sensu＿stricto＿5 in root endophytic bacteria increased rapidly, becoming the most dominant genus(45.02%) by the end of the exposure period. In contrast, Betaproteobacteriales remained the dominant order in the rhizosphere bacterial community throughout the experiment, with its relative abundance increasing continuously over time. The proportion of ARB-carrying endophytic bacteria initially decreased and then increased during exposure, showing a significant positive correlation with the relative abundances of Clostridium＿sensu＿stricto＿5, Clostridium＿sensu＿stricto＿1, Bacillus, and Paenibacillus(P<0.05). In summary, exogenous ARB exposure significantly inhibits wheat seedling growth and alters the community structure of both root endophytic and rhizosphere bacteria. Sustained ARB exposure leads to the transfer of exogenous ARGs to root endophytes, and Clostridium＿sensu＿stricto species may act as potential hosts for ARGs in wheat seedling roots.更多还原