State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China.
University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China.
Ecotoxicol Environ Saf. 2019 Nov 15;183:109538. doi: 10.1016/j.ecoenv.2019.109538. Epub 2019 Aug 8.
It is well established that arsenic (As) pollution has a severe threat to food security and soil non-target organisms, however, its influences on soil fauna gut microbiota are poorly understood. The gut microbiota of soil fauna play an important role in host health and nutrient cycling. Here, we used dietary exposure to investigate the effects of As on the mortality and gut microbiota of two model soil collembolans (Folsomia candida and Onychiurus yodai) and determine the accumulation of As in collembolan body tissues. The results showed that, although As exposure did not induce the mortality of the two species, dose dependence of As accumulation was indeed detected in their body tissues. Oral As exposure (500 μg g yeast) significantly altered the community structure (P < 0.05) of F. candida gut microbiota and reduced its diversity (by more than 20%; P < 0.05) compared to the control; however, no significant effects were observed in O. yodai gut microbiota. The two collembolan species possess significantly different gut microbiota (P < 0.05), which may partly explain the differences of the two collembolan gut microbiota response to As exposure. We further found that the genera Ochrobactrum, Geobacter and Staphylococcus were sensitive to As exposure in F. candida (P < 0.05), but these bacteria were low abundance and not altered in O. yodai. Moreover, the relative abundance of these bacteria was significantly correlated with As bioaccumulation in F. candida body tissues (P < 0.05, R > 0.6). Higher As bioaccumulation factor was also found in O. yodai body tissues compared to the F. candida. These results indicate that collembolan gut microbiota present a species-specific response to As and may be a more sensitive indicator than the mortality of collembolan.
砷（As）污染对食品安全和土壤非靶标生物构成严重威胁，这已得到充分证实，然而，其对土壤无脊椎动物肠道微生物群的影响仍知之甚少。土壤无脊椎动物的肠道微生物群在宿主健康和养分循环中发挥着重要作用。在这里，我们使用饮食暴露法研究了砷对两种模式土壤弹尾目动物（Folsomia candida 和 Onychiurus yodai）死亡率和肠道微生物群的影响，并确定了砷在弹尾目动物体组织中的积累。结果表明，尽管砷暴露没有诱导两种物种的死亡，但确实在它们的体组织中检测到砷的积累与剂量呈依赖性。口服砷暴露（500μg g 酵母）显著改变了 F. candida 肠道微生物群的群落结构（P<0.05），并使其多样性降低（超过 20%；P<0.05）；而 O. yodai 肠道微生物群则没有观察到显著影响。两种弹尾目动物具有明显不同的肠道微生物群（P<0.05），这可能部分解释了两种弹尾目动物肠道微生物群对砷暴露反应的差异。我们进一步发现，在 F. candida 中，Ochrobactrum、Geobacter 和 Staphylococcus 等属对砷暴露敏感（P<0.05），但这些细菌在 O. yodai 中的丰度较低，且没有变化。此外，这些细菌的相对丰度与 F. candida 体组织中砷的生物积累显著相关（P<0.05，R>0.6）。O. yodai 体组织中的砷生物积累因子也高于 F. candida。这些结果表明，弹尾目动物的肠道微生物群对砷表现出种特异性反应，可能比弹尾目动物的死亡率更敏感。
