植物-外生菌根真菌-细菌三方互作体系与磷素循环相关的研究进展

Research advances in the plant-ectomycorrhizal fungus-bacteria tripartite system in relation to phosphorus cycling

摘要:

在自然土壤中磷素主要以螯合态无机磷等稳定形式存在，有效磷含量较低。木本植物为应对磷胁迫通常与外生菌根真菌形成菌根共生体系以增强其对磷素的吸收。相关研究表明，外生菌根真菌自身溶解螯合态无机磷的能力有限，但其可通过释放特定的化合物招募土壤中的溶磷相关功能细菌类群聚集在真菌菌丝际，协助解吸螯合态无机磷。然而，目前鲜有关于植物-外生菌根真菌-细菌三者联合体系在磷素循环中作用的综述性分析报道。本文提出了植物-外生菌根真菌-细菌三者联合体系的概念，解析了外生菌根真菌、菌根辅助细菌和宿主植物三者对磷素循环的作用及其生理生化和分子机制，并展望了三者联合体系促进植物磷素吸收的研究前景。

Abstract:

In natural soils, phosphorus predominantly exists in stable forms such as chelated inorganic phosphorus, resulting in low levels of available phosphorus. To cope with phosphorus limitation, woody plants typically form symbiotic associations with ectomycorrhizal fungi (ECMF) to enhance phosphorus acquisition. Studies have indicated that ECMF exhibit limited capacity to directly solubilize chelated inorganic phosphorus. However, they can recruit phosphate-solubilizing bacteria in the hyphosphere by releasing specific compounds, thereby facilitating the desorption of chelated inorganic phosphorus. Nevertheless, comprehensive reviews analyzing the role of plant-ECMF-bacteria tripartite systems in phosphorus cycling remain scarce. This article introduces the conceptual framework of plant-ECMF-bacteria tripartite systems, elucidates the physiological, biochemical, and molecular mechanisms underlying phosphorus cycling among ECMF, mycorrhiza helper bacteria, and host plants, and discusses future research directions for optimizing plant phosphorus acquisition through the tripartite systems.