College of Horticulture and Gardening, Yangtze University, 434025, Jingzhou, Hubei, China.
World J Microbiol Biotechnol. 2022 Jul 14;38(9):159. doi: 10.1007/s11274-022-03336-y.
The most dominant arbuscular mycorrhizal (AM) symbiont can be established on roots of most terrestrial plants by beneficial AM fungi. A type of polycationic and aliphatic compounds, polyamines (PAs), are involved in plant physiological activities including stress responses. Interestingly, small amounts of PAs such as putrescine (Put) and spermidine (Spd) were found in AM fungal spores, and they are considered to be a component involved in mycorrhizal development, including mycorrhizal colonization, appressoria formation, spore germination and mycelial growth. Thus, PAs are regulatory factors in plant-AM symbiosis. Inoculation of AM fungi also affects the metabolism of endogenous PAs in host plants, including PAs synthesis and catabolism, thus, regulating various physiological events of the host. As a result, there seems to be a dialogue between PAs and AM fungi. Existing knowledge makes us understand that endogenous or exogenous PAs are an important regulator factor in the growth of AM fungi, as well as a key substance to colonize roots, which further enhances mycorrhizal benefits in plant growth responses and root architecture. The presence of AM symbiosis in roots alters the dynamic balance of endogenous PAs, triggering osmotic adjustment and antioxidant defense systems, maintaining charge balance and acting as a stress signalling molecule, which affects various physiological activities, such as plant growth, nutrient acquisition, stress tolerance and improvement of root architecture. This review mainly elucidated (i) what is the role of fungal endogenous PAs in fungal growth and colonization of roots in host plants? (ii) how AM fungi and PAs interact with each other to alter the growth of fungi and plants and subsequent activities, providing the reference for the future combined use of AM fungi and PAs in agricultural production, although there are still many unknown events in the dialogue.
最占优势的丛枝菌根（AM）共生体可以通过有益的 AM 真菌在大多数陆生植物的根系上建立。多胺（PAs）是一类带正电荷的脂肪族化合物，参与植物的生理活动，包括应激反应。有趣的是，AM 真菌孢子中发现了少量的多胺，如腐胺（Put）和亚精胺（Spd），它们被认为是参与菌根发育的组成部分，包括菌根定殖、附着胞形成、孢子萌发和菌丝生长。因此，PAs 是植物-AM 共生的调节因子。接种 AM 真菌也会影响宿主植物内源性 PAs 的代谢，包括 PAs 的合成和分解代谢，从而调节宿主的各种生理事件。因此，似乎 PAs 和 AM 真菌之间存在对话。现有知识使我们了解到，内源性或外源性 PAs 是 AM 真菌生长的重要调节因子，也是定殖根系的关键物质，进一步增强了 AM 真菌在植物生长反应和根系结构中的益处。根系中 AM 共生体的存在改变了内源性 PAs 的动态平衡，引发渗透调节和抗氧化防御系统，维持电荷平衡并作为应激信号分子，影响各种生理活动，如植物生长、养分获取、应激耐受和根系结构的改善。本综述主要阐明了：（i）真菌内源性 PAs 在真菌生长和宿主植物根系定殖中的作用是什么？（ii）AM 真菌和 PAs 如何相互作用，改变真菌和植物的生长以及随后的活动，为未来在农业生产中联合使用 AM 真菌和 PAs 提供参考，尽管在对话中仍有许多未知事件。
