Wang Yan-Zi, Zhou Shu-Yi-Dan, Zhou Xin-Yuan, An Xin-Li, Su Jian-Qiang
Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, China; Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe District, Guangzhou 510650, China.
Sci Total Environ. 2023 Feb 20;860:160515. doi: 10.1016/j.scitotenv.2022.160515. Epub 2022 Nov 25.
Soil amendment with manure compost and biochar is widely adopted to improve soil fertility and promote plant growth, and their effects on soil microbial communities and resistome have been well documented. However, there is sparse information regarding their effects on vegetable endophytes, which represent a major source of human exposure to pathogens and antibiotic resistance genes (ARGs) when eaten raw. Here, we investigated the impacts of manure compost or biochar addition on the bacterial community compositions and ARGs in the soil-lettuce continuum including soil, seed, leaf, and root samples. A total of 137 ARGs and 31 mobile genetic elements (MGEs) were detected in all the samples after 60 days of cultivation. The relative abundance of ARGs and the diversity of bacteria communities presented a consistent decreasing trend from soil to root endophytes, then leaf endophytes. Manure compost addition increased the diversity and abundance of ARGs in soil, while significant changes in the ARG profiles and bacterial communities were not observed in leaf endophytes after manure compost or biochar addition, or both. Bipartite networks analysis suggested that seed microbiome was one of the major sources of plant endophytes and ARGs. Twenty potential human pathogens were isolated from lettuce, indicating potential exposure risk to pathogens via the consumption of raw lettuce. These results suggest limited impacts of manure compost and biochar addition on lettuce endophytes and highlight the contribution of seed microbiome to endophyte ARG profiles.
施用粪肥堆肥和生物炭改良土壤已被广泛采用，以提高土壤肥力并促进植物生长，其对土壤微生物群落和抗性组的影响已有充分记录。然而，关于它们对蔬菜内生菌影响的信息却很少，而蔬菜内生菌是人类在生食时接触病原体和抗生素抗性基因（ARGs）的主要来源。在此，我们研究了添加粪肥堆肥或生物炭对土壤-生菜连续体（包括土壤、种子、叶片和根系样本）中细菌群落组成和ARGs的影响。种植60天后，在所有样本中总共检测到137种ARGs和31种可移动遗传元件（MGEs）。从土壤到根内生菌，再到叶内生菌，ARGs的相对丰度和细菌群落多样性呈现出一致的下降趋势。添加粪肥堆肥增加了土壤中ARGs的多样性和丰度，然而，添加粪肥堆肥或生物炭，或两者都添加后，在叶内生菌中未观察到ARG谱和细菌群落的显著变化。二分网络分析表明，种子微生物组是植物内生菌和ARGs的主要来源之一。从生菜中分离出20种潜在的人类病原体，表明食用生生菜存在病原体潜在暴露风险。这些结果表明，添加粪肥堆肥和生物炭对生菜内生菌的影响有限，并突出了种子微生物组对内生菌ARG谱的贡献。
