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草业学报 ›› 2024, Vol. 33 ›› Issue (2): 125-137.DOI: 10.11686/cyxb2023106

• 研究论文 • 上一篇    

高寒草甸退化程度对优势物种根际土壤真菌群落和生态网络的影响

马源1(), 王晓丽1(), 马玉寿1, 张德罡2   

  1. 1.青海大学畜牧兽医科学院,三江源区高寒草地生态教育部重点实验室,青海省高寒草地适应性管理重点实验室,青海 西宁 810016
    2.甘肃农业大学草业学院,草业生态系统教育部重点实验室,甘肃 兰州 730070
  • 收稿日期:2023-04-06 修回日期:2023-04-24 出版日期:2024-02-20 发布日期:2023-12-12
  • 通讯作者: 马源,王晓丽
  • 作者简介:wxl.yu@163.com
    E-mail: mayuan608@163.com
    马源(1989-),男,回族,甘肃嘉峪关人,副研究员,博士。E-mail: mayuan608@163.com
  • 基金资助:
    青海省自然科学基金(2022-ZJ-979Q);国家自然科学基金地区基金(32260327);国家自然科学基金重点项目(32230068)

Effects of the degree of alpine meadow degradation on the rhizosphere soil fungal community and the ecological network of dominant species

Yuan MA1(), Xiao-li WANG1(), Yu-shou MA1, De-gang ZHANG2   

  1. 1.Academy of Animal and Veterinary Science,Qinghai University,Key Laboratory of Alpine Grassland Ecosystem in the Three-River-Source,Ministry of Education,Qinghai Provincial Key Laboratory of Adaptive Management on Alpine Grassland,Xining 810016,China
    2.College of Prataculture Science,Gansu Agricultural University,Key Laboratory of Grassland Ecosystem of the Ministry of Education,Lanzhou 730070,China
  • Received:2023-04-06 Revised:2023-04-24 Online:2024-02-20 Published:2023-12-12
  • Contact: Yuan MA,Xiao-li WANG

摘要:

为明确高寒草甸退化过程中优势物种改变对根际土壤真菌群落多样性及其稳定性的影响,以青藏高原东缘4个不同退化程度(未退化、轻度退化、中度退化和重度退化)高寒草甸为研究对象,采用ITS rRNA基因测序技术,结合FUNGuild预测和分子生态网络模型方法,分析了高寒草甸退化程度对根际真菌群落结构、功能群和分子生态网络的影响。结果表明:草地退化程度对根际土壤真菌Alpha多样性无显著影响,但显著改变根际土壤真菌的Beta多样性;退化程度仅对根际真菌优势种群的相对丰度产生影响,对真菌优势种群没有影响,4个不同退化程度高寒草甸根际土壤中真菌优势种群均为担子菌门、被孢霉门和子囊菌门;通过线性判别分析发现了29个生物标志物,其中大部分属于担子菌门和子囊菌门;草地退化过程中根际真菌群落主要由共生营养型向腐生营养型转变;网络分析发现,退化高寒草甸根际真菌群落各可操作分类单元(OTU)主要以负相关关系为主,并且退化程度越高负相关程度越强烈。同时结合网络拓扑参数,草地退化程度的加剧将会导致根际真菌结构呈更为松散和不稳定的态势。综上所述,高寒草甸退化程度对优势物种根际真菌群落组成、结构和功能类型产生了显著影响,并降低了真菌群落的稳定性和复杂性。研究结果为深入理解高寒草甸根际微生态的适应性机制提供了科学理论依据。

关键词: 高寒草甸, 草地退化, 优势物种, 根际土壤真菌群落, 分子生态网络

Abstract:

Changes in the diversity and stability of the rhizosphere fungi community can reveal the adaptive mechanisms of microorganisms to degraded ecosystems. The aim of this study was to clarify the influence of changes in dominant species on the diversity and stability of rhizosphere fungal communities. Samples were collected from alpine meadows on the eastern edge of the Qinghai-Tibetan Plateau with four different degrees of degradation (non-degraded grassland, lightly degraded grassland, moderately degraded grassland, and severely degraded grassland). A combination of ITS rRNA gene sequencing technology, FUNGuild prediction, and molecular ecological network modeling methods was used to analyze the effects of alpine meadow degradation on rhizosphere fungal structure, functional groups, and molecular ecological networks. The results showed that the degree of grassland degradation significantly affected the Beta diversity, but not the Alpha diversity of rhizosphere soil fungi. The degree of degradation only affected the relative abundance of taxa, and had no effect on the dominant fungal communities. The dominant fungal populations in the rhizosphere soils of grasslands with different degrees of degradation were Basidiomycota, Mortierella, and Ascomycota. Linear discriminant analysis Effect Size (LEfSe) identified 29 biomarkers, most of which corresponded to Basidiomycota and Ascomycota. There was a major shift of rhizosphere fungal communities from symbiotic to saprophytic nutrient types with increasing severity of grassland degradation. The network analysis showed that there was a negative correlation between the number of operational taxonomic units (OTUs) of the rhizosphere fungal community and the degree of degradation of the grassland. Combined with data of the network topology parameters, these findings indicate that increasing severity of grassland degradation leads to a looser and more unstable rhizosphere fungal structure. In conclusion, alpine meadow degradation significantly changed the composition, structure, and functional types of rhizosphere fungal communities, especially those of dominant species, and reduced the stability and complexity of fungal communities. These results provide a scientific basis for further research on the adaptive responses of rhizosphere microbe communities to degradation of alpine meadows.

Key words: alpine meadow, meadow degradation, dominant species, rhizosphere soil fungal communities, molecular ecological networks