State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
College of Life Science, Nanjing Normal University, Nanjing, 210023, China.
Microbiome. 2020 Oct 2;8(1):142. doi: 10.1186/s40168-020-00918-6.
The soil mycobiome is composed of a complex and diverse fungal community, which includes functionally diverse species ranging from plant pathogens to mutualists. Among the latter are arbuscular mycorrhizal fungi (AMF) that provide phosphorous (P) to plants. While plant hosts and abiotic parameters are known to structure AMF communities, it remains largely unknown how higher trophic level organisms, including protists and nematodes, affect AMF abundance and community composition.
Here, we explored the connections between AMF, fungivorous protists and nematodes that could partly reflect trophic interactions, and linked those to rhizosphere P dynamics and plant performance in a long-term manure application setting. Our results revealed that manure addition increased AMF biomass and the density of fungivorous nematodes, and tailored the community structures of AMF, fungivorous protists, and nematodes. We detected a higher abundance of AMF digested by the dominant fungivorous nematodes Aphelenchoides and Aphelenchus in high manure treatments compared to no manure and low manure treatments. Structural equation modeling combined with network analysis suggested that predation by fungivorous protists and nematodes stimulated AMF biomass and modified the AMF community composition. The mycorrhizal-fungivore interactions catalyzed AMF colonization and expression levels of the P transporter gene ZMPht1;6 in maize roots, which resulted in enhanced plant productivity.
Our study highlights the importance of predation as a key element in shaping the composition and enhancing the biomass of AMF, leading to increased plant performance. As such, we clarify novel biological mechanism of the complex interactions between AMF, fungivorous protists, and nematodes in driving P absorption and plant performance. Video Abstract.
土壤真菌群落由复杂多样的真菌组成，包括从植物病原体到共生体的功能多样的物种。后者包括为植物提供磷（P）的丛枝菌根真菌（AMF）。虽然已知植物宿主和非生物参数会影响 AMF 群落结构，但对于包括原生动物和线虫在内的更高营养级生物如何影响 AMF 丰度和群落组成，仍知之甚少。
在这里，我们探讨了 AMF、食真菌原生动物和线虫之间的联系，这些联系部分反映了营养相互作用，并将这些联系与根际 P 动态和长期施用有机肥条件下的植物性能联系起来。我们的研究结果表明，有机肥的添加增加了 AMF 的生物量和食真菌线虫的密度，并调整了 AMF、食真菌原生动物和线虫的群落结构。与无肥和低肥处理相比，我们在高肥处理中检测到更多由优势食真菌线虫 Aphelenchoides 和 Aphelenchus 消化的 AMF。结构方程模型结合网络分析表明，食真菌原生动物和线虫的捕食作用刺激了 AMF 的生物量，并改变了 AMF 群落组成。菌根菌-食真菌相互作用促进了 AMF 的定植和玉米根系中 P 转运蛋白基因 ZMPht1;6 的表达水平，从而提高了植物的生产力。
我们的研究强调了捕食作用作为塑造 AMF 组成和增强其生物量的关键因素的重要性，从而提高了植物的性能。因此，我们阐明了 AMF、食真菌原生动物和线虫之间复杂相互作用促进 P 吸收和植物性能的新生物学机制。
