稻田生态系统中丛枝菌根真菌的研究进展

Research progress of arbuscular mycorrhizal fungi in paddy fields

摘要:

水稻是世界上近一半人口的主粮作物，也被认为是研究丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)与非豆科植物共生的模式寄主植物。由于研究手段的限制，长期以来对稻田AMF多样性和生态功能的认识不够深入。近10年来，随着高通量测序技术的发展，越来越多的研究表明，AMF在稻田生态系统中普遍存在。新技术的发展极大地推动了稻田生态系统中AMF生态功能及其与水稻互作的研究。本文综述了稻田生态系统丛枝菌根(arbuscular mycorrhizal,AM)共生体的建立、AMF的多样性及其影响因素、AMF的生态功能、AMF在水稻栽培中的潜在应用等，并对未来AMF与水稻研究进行了展望。研究表明，AM共生体的建立依赖AMF和水稻间一系列复杂的信号识别、交换和传导机制；相较于稻田湿地环境，旱作环境水稻根中AMF的定殖率更高，而且受寄主植物、环境因子和栽培管理措施等因素影响；AMF在调控水稻生长、营养吸收、抵御环境胁迫、降低稻田甲烷(CH₄)和氧化亚氮(N₂O)排放等方面发挥着重要功能；AMF与其他微生物联合作用可以更好地帮助水稻吸收养分和抵御环境胁迫。基于稻田生态系统AMF研究进展和未来发展趋势的分析，本文讨论了该研究领域目前存在的问题和不足，指出后续研究应深入探讨AMF多样性水平及其生态功能之间的联系，加深对水稻-AMF相互识别的信号机制及共生建立和维持的分子级联反应的认识，并深入挖掘AMF促进水稻养分吸收、增强水稻抗逆性、降低稻田温室气体排放等分子机制。

Abstract:

Rice feeds nearly half of the world’s population, and it is also considered as the model host plant for studying the symbiosis between arbuscular mycorrhizal fungi (AMF) and non-legumes. The diversity and ecological roles of AMF in paddy fields have not been well understood for a long time due to the limitation of research methods. Studies have demonstrated that AMF are ubiquitous in paddy fields with the development of high-throughput sequencing technology in the last decade. The application of new techniques greatly promoted the research on the ecological roles of AMF and the interactions between AMF and rice in paddy ecosystems. In this review, we summarized the process of the establishment of arbuscular mycorrhizal (AM) symbionts, the diversity and influencing factors of AMF, and the ecological roles of AMF in paddy ecosystems. Furthermore, the potential application of AMF in rice cultivation and future research on the interactions between AMF and rice have been prospected. The establishment of AM symbionts depends on a series of complex signal recognition, exchange, and conduction between AMF and rice. The AMF colonization rate of rice plants is higher in the upland environment than that in the paddy environment, and it is affected by host plants, environmental factors, and cultivation management measures. AMF play a key role in regulating rice growth and nutrient absorption, resisting environmental stress, and reducing methane (CH₄) and nitrous oxide (N₂O) emissions from paddy fields. AMF can act together with other microorganisms to help rice absorb nutrients and resist environmental stresses. This paper reviews the research progress and development trends of AMF in paddy fields and discusses the inadequacy in this research field. In the future, efforts should be made to explore the relationship between the diversity and ecological roles of AMF, the mutual signal recognition between rice and AMF, and the molecular cascade reactions in the establishment and maintenance of AM symbiosis. Moreover, it is essential to understand the underlying molecular mechanisms of AMF promoting rice nutrient absorption, enhancing rice stress resistance, and reducing greenhouse gas emissions from rice fields.