National Natural Science Foundation of China (No. 41622104)
根际细菌-真菌群落的互作关系对于土壤养分转化有重要意义。为研究施加生物质炭对根际土壤细菌-真菌之间相互作用的影响，通过盆栽试验，比较未施加生物质炭的对照和施加2%生物质炭处理条件下，黑麦草根际细菌-真菌群落间的互作网络及影响因素。结果表明，施加生物质炭后的细菌-真菌群落之间的互作网络具有更复杂的联系，节点数和互作关系增加，细菌内部以及细菌与真菌之间的种间积极作用显著增强（P< 0.05）；模块化分析对照和处理下的互作网络，均发现存在两个具有高度互连节点的模块化结构。网络中起到关键连接作用的类群在对照中为细菌中的孙修勤菌（Sunxiuqinia）和真菌中的毕赤酵母（Pichia），施加生物质炭处理后为细菌中的黄杆菌（Flavobacterium）。Mantel检验分析表明，施加生物质炭处理后土壤pH（r = 0.385，P = 0.003）和土壤铵态氮（r = 0.501，P = 0.003）对细菌-真菌群落相互作用的影响显著增强。
【Objective】 Rhizosphere is a specific compartment that is significantly influenced by soil microorganisms in the plant root system in soil. Rhizosphere extends from the surface of the main root for a few millimetres, and is an important zone where plant-soil-microorganism interactions occur. In the rhizosphere, bacteria and fungi coexist and interact with each other, playing a critical role in recycling of nutrients in the ecosystem and sustaining of plant health and growth. Ecological network analysis can visualize interactions between microbial communities, and uncover co-occurrence patterns of the species in microhabitats and their main influencing factors, which provides a new approach to explaining complex structure of the microbial communities. Network analysis can also be used to explore mechanisms of microbial interactions driving biogeochemical coupling of important elements in soil, which is an important step towards predicting and improving service functions of a soil ecosystem. Unique in structure and composition, biochar can improve soil properties in a number of aspects, for instance, promoting formation of soil aggregates, enhancing cation exchange capacity, nutrient absorption capacity and water holding capacity, and dulling excessive acidification. So it can be applied beneficially to soil amelioration and raising of crop yield. In addition, the unique aromatic surface, excellent porous structure and high moisture and nutrient adsorption capacity of biochar can also provide soil microorganisms, such as bacteria and fungi, with benign habitats, and hence increase biomass of the microorganisms. The application of biochar can alter structure and enzyme activity of the microbial community, which benefits accumulation of soil organic matter and transformation of soil nutrients and then indirectly improves growth of the plants. Therefore, a comprehensive understanding of the effects of biochar on the interactions between bacterial and fungal communities in rhizosphere soil is of great significance to how to improve soil nutrient transformation. 【Method】 In order to explore effects of biochar on interactions between bacteria and fungi in rhizosphere soil, a pot experiment was designed to have CK and a treatment of adding 2% (w/w) biochar and performed for comparison in interaction network between rhizosphere bacteria and fungi and its affecting factors. The soil used in the experiment was collected from the topsoil layer (0~10 cm) of a paddy field in Changzhou, Jiangsu Province, air-dried, screened with a sieve 2 cm in mesh, and ground fine. Then the soil homogeneous in texture was left in rest for 24 hours, before being put in pots, 3 kg each. Full ryegrass seeds were sown into the pots, 30 each. Soil and plant root samples were collected from the pots on the 0th, 5th, 10th, 15th, 20th, 25th, 30th, 35th and 40th days after germination of the seeds, from three pots each time as replicate. So the experiment had a total of 54 pots of ryegrass plants. The samples were analyzed separately and soil geochemical properties, rhizosphere microorganisms, and morphological parameters of the ryegrass roots were determined. 【Result】 Network analysis shows that in the treatment, the association between bacteria and fungi in their co-occurrence network became more complicated with number of nodes and interaction enhanced. Positive interactions within the bacterial community and between bacteria and fungi communities were significantly enhanced (P < 0.05). Modular analysis of the interaction networks in CK and Treatment found two modular structures with highly interconnected nodes. In the treatment, Flavobacterium was found to be the key group of the co-occurrence network, while in CK, Sunxiuqiniaand Pichia were. Mantel test indicates that soil pH (r= 0.385, P = 0.003) and soil ammonium nitrogen (r = 0.501, P = 0.003) had more significant effects on the interaction between rhizosphere bacteria and fungi in the treatment. 【Conclusion】 Application of biochar significantly enhances interactions between bacterial-fungal communities in the rhizosphere soil, while improving positive associations within the bacteria community and between bacteria and fungi.
马泊泊,黄瑞林,张 娜,孙 波,梁玉婷.秸秆生物质炭对根际土壤细菌-真菌群落分子生态网络的影响[J].土壤学报,2019,56(4):964-974. DOI:10.11766/trxb201809030443 MA Bobo, HUANG Ruilin, ZHANG Na, SUN Bo, LIANG Yuting. Effect of Straw-derived Biochar on Molecular Ecological Network between Bacterial and Fungal Communities in Rhizosphere Soil[J]. Acta Pedologica Sinica,2019,56(4):964-974.复制