Earthworm (Pheretima guillelmi) was selected as the model animal. Combination of in situ determination, high-throughput sequencing and biochemical analysis, the results indicated that the production of Fe(Ⅱ) was highest in the glucose treatment group and lowest in the amino acid setup. During the iron(Ⅲ) reduction process, the content of surface-adsorbed Fe(Ⅱ) was the highest, ranging from 0.6 to 24.38mmol/L;whereas the content of ionic Fe(Ⅱ) was the lowest, ranging from 0.02 to 2.21mmol/L. The community structure of iron(Ⅲ)-reducing bacteria was significantly influenced by the type of organic matter, and the dominant iron(Ⅲ)-reducing bacteria in different treatment groups were diverse. Additionally, the iron(Ⅲ) reduction process was accompanied by the generation of reactive oxygen species (ROS). The content of hydrogen peroxide (H2O2) was the highest, ranging from 0.32 to 0.73mmol/L, and be show a significant positive correlation with the contents of ionic Fe2+, surface-adsorbed Fe(Ⅱ), and high-crystalline iron, while exhibiting a significant negative correlation with the content of iron in organic complex state. Hydroxyl radical (•OH) has a significant positive correlation with ionic Fe2+, adsorbed Fe(Ⅱ), and high-crystalline iron. Superoxide anion (O2•−)has a significant positive correlation with low-crystalline iron and a significant negative correlation with adsorbed Fe(Ⅱ) and high-crystalline iron. The research results provide a new perspective for understanding the role of earthworms gut microbiota in soil iron cycling and ROS formation, which can be applied for pollutant control and degradation.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |