College of Life Sciences, Shaanxi Normal University, Xi'an 710119, PR China.
College of Life Sciences, Shaanxi Normal University, Xi'an 710119, PR China.
Sci Total Environ. 2019 Nov 25;693:133548. doi: 10.1016/j.scitotenv.2019.07.354. Epub 2019 Jul 23.
Plant invasion typically alters the microbial communities of soils, which affects ecosystem carbon (C) and nitrogen (N) cycles. The responses of the soil fungal communities to plant invasion along its chronosequence remain poorly understood. For this study, we investigated variations in soil fungal communities through Illumina MiSeq sequencing analyses of the fungal internal transcribed spacer (ITS) region, and quantitative polymerase chain reaction (qPCR), along a chronosequence (i.e., 9-, 13-, 20- and 23-year-old) of invasive Spartina alterniflora. We compared these variations with those of bare flat in a Chinese Yellow Sea coastal wetland. Our results highlighted that the abundance of soil fungi, the number of operational taxonomic units (OTUs), species richness, and Shannon diversity indices for soil fungal communities were highest in 9-year-old S. alterniflora soil, which gradually declined along the invasion chronosequence. The relative abundance of copiotrophic Basidiomycota revealed significant decreasing trend, while the relative abundance of oligotrophic Ascomycota gradually increased along the S. alterniflora invasion chronosequence. The relative abundance of soil saprotrophic fungi (e.g., undefined saprotrophs) was gradually reduced while symbiotic fungi (e.g., ectomycorrhizal fungi) and pathotrophic fungi (e.g., plant and animal pathogens) progressively increased along the S. alterniflora invasion chronosequence. Our results suggested that S. alterniflora invasion significantly altered soil fungal abundance and diversity, community composition, trophic modes, and functional groups along a chronosequence, via substantially reduced soil litter inputs, and gradually decreased soil pH, moisture, and soil nutrient substrates along the invasion chronosequence, from 9 to 23 years. These changes in soil fungal communities, particularly their trophic modes and functional groups along the S. alterniflora invasion chronosequence could well impact the decomposition and accumulation of soil C and N, while potentially altering ecosystem C and N sinks in a Chinese Yellow Sea coastal wetland.
植物入侵通常会改变土壤中的微生物群落，从而影响生态系统的碳（C）和氮（N）循环。然而，人们对植物入侵沿时间序列对土壤真菌群落的响应仍知之甚少。在这项研究中，我们通过对入侵植物互花米草（ Spartina alterniflora ）的内转录间隔区（ ITS ）进行 Illumina MiSeq 测序分析和定量聚合酶链反应（ qPCR ），研究了土壤真菌群落的变化，并沿其时间序列（即 9 、 13 、 20 和 23 年）进行了研究。我们将这些变化与中国黄海沿海湿地裸露滩涂的变化进行了比较。结果表明，土壤真菌丰度、OTU 数量、物种丰富度和土壤真菌群落 Shannon 多样性指数在 9 年生互花米草土壤中最高，随着入侵时间序列的延长而逐渐降低。富营养型担子菌的相对丰度呈显著下降趋势，而寡营养型子囊菌的相对丰度则逐渐增加。随着互花米草入侵时间序列的延长，土壤腐生真菌（如未定义腐生真菌）的相对丰度逐渐降低，而共生真菌（如外生菌根真菌）和病原真菌（如植物和动物病原体）的相对丰度逐渐增加。这些结果表明，互花米草入侵通过减少土壤凋落物的输入，以及随着入侵时间序列的延长，土壤 pH 值、水分和土壤养分底物逐渐降低，显著改变了土壤真菌的丰度和多样性、群落组成、营养方式和功能群。这些土壤真菌群落的变化，特别是其在互花米草入侵时间序列上的营养方式和功能群，可能会影响土壤 C 和 N 的分解和积累，从而改变中国黄海沿海湿地的生态系统 C 和 N 汇。
