|Alternative Title||Study on the structure and distribution of soil prokaryotic microbial community in Qinghai-Tibetan plateau|
|Place of Conferral||兰州|
|Keyword||青藏高原 高通量测序 原核微生物群落 不同生境 土壤理化特性|
本研究以青藏高原不同空间（32个样地）土壤样品为研究对象，采用Illumina MiSeq高通量测序和qPCR技术，研究了青藏高原不同空间尺度及高寒草甸（M）、高寒草原（S1）、荒漠化草原（S2）三种不同生境土壤中细菌、古菌群落结构以及细菌、古菌16srRNA基因丰度，探讨了细菌、古菌群落分布格局特征及其影响因子。实验结果如下：1.不同空间土壤中原核微生物高通量测序数据统计。高通量测序结果显示，16srRNA基因的V3-V4区测序优化序列抽平后每个样品分别得到14619条细菌和24282条古菌优化序列，优化序列比对后分别划分为6384个细菌和5049个古菌OTU。细菌优化序列的99%能分到门水平（41个门），主要包括Actinobacteria（放线菌门）、Proteobacteria（变形菌门）、Chloroflexi（绿弯菌门）等；古菌优化序列则95%能分到门水平（9个门），主要是Thaumarchaeota （奇古菌门）、Archaea -unclassified、Euryarchaeota（广古菌门）。细菌群落分类学注释到纲、目、属分类水平的比例分别为98.4%、83.2%和44.4%；古菌分类学注释到纲、目、属分类水平的比例就比较低，分别为94.9%、2.4%和9.7%。2.不同空间土壤中原核微生物群落结构分析。高通量测序及qPCR结果显示，土壤细菌群落结构α多样性高于土壤古菌群落结构α多样性，同时，青藏高原土壤中细菌16srRNA基因的拷贝数（1.5×109~4.5×1011）高于土壤古菌（8.5×106~1.7×109）16srRNA基因的拷贝数，细菌16srRNA基因丰度比古菌16srRNA基因丰度高两个数量级。细菌、古菌群落结构、16srRNA基因丰度与土壤特性、空间因子间分析结果显示，土壤理化特性对细菌、古菌群落结构的影响更为显著。土壤pH对土壤细菌、古菌群落结构的影响最大，原核微生物16srRNA基因丰度同样由土壤pH影响。影响土壤细菌、古菌群落结构的次要土壤理化因子是土壤有机质。3.青藏高原不同生境土壤中原核微生物群落结构分析。土壤原核微生物群落结构PCoA分析结果结合采样样地的植被类型可将样本分为三种不同生境：高寒草甸（M）、高寒草原（S1）和荒漠化草原（S2）。对土壤原核微生物群落结构进行的差异分析结果显示，高寒草甸土壤中细菌群落α多样性以及细菌丰富度比高寒草原及荒漠化草原的细菌群落α多样性及丰富度显著低，而细菌16srRNA基因丰度在高寒草甸显著高（P<0.001）。古菌群落α多样性在三种不同生境没有显著差异（P>0.05），而古菌16srRNA基因丰度在比较贫瘠的高寒草原及荒漠化草原比较高（P<0.01）。土壤细菌、古菌的群落组成也在三种不同生境中均有所差异（P<0.01）。土壤理化特性与土壤原核微生物群落结构间的相关分析显示，土壤理化特性在不同生境中存在显著差异，土壤理化差异引起土壤原核微生物群落结构差异及丰度的变化（P<0.01）。在高寒草甸中，土壤pH影响土壤原核微生物群落结构，而在高寒草原、荒漠化草原主要由土壤营养元素限制。
The Tibetan plateau, as main livestock carrying ecosystem, is the most excellent natural grazing grassland, and has unique, abundant species resources. Thus, much attention has been paid to the ecological and economic value of Tibetan plateau. The main land use pattern of Tibetan plateau is grazing, and long-term grazing can lead to degradation and desertification of grassland. At the same time, the Tibetan plateau is a sensitive area responding to the global change, particularly to the global warming. The decrease of the ecological function stability at the extreme environment will affect the stability of the ecosystem in China, even, the global ecosystem. Soil prokaryotic microorganisms, as participants of the biogeochemical cycles, directly or indirectly affect the stability of ecosystem.
Here we investigated the soil prokaryotic microbiology community in different scale space and habitats(32 sample sites) in the Tibetan plateau, using Illumina MiSeq high-throughput sequencing technology and qPCR technology. Studied the soil bacterial and archaeal community structure, abundance of bacterial and archaeal 16srRNA gene in different scale range and in three different habitats, including alpine meadow, alpine steppe, desertification meadow, explored the structure of bacterial and archaeal community diversity, abundance and revealed the response of bacterial, archaeal community structure and abundance to environmental factors. The experimental results are as follows:1. The high-throughput sequencing results of 16srRNA gene of soil bacteria and archae.The results of high-throughput sequencing showed, the number of 16srRNA gene sequences were normalized to 14619 and 24282 per sample for bacteria and archaea respectively. 6384 bacterial OTUs and 5049 archaeal OTUs were mapped by comparison at 97% similarity level. 99% of bacterial optimization sequences can be divided into phylum levels (41 phyla), mainly including Actinobacteria, Proteobacteria, Chloroflexi, etc. And 95% of Archaeal sequences can be divided into phylum level (9 phyla), mainly including Thaumarchaeota, Archaea unclassified, Euryarchaeota. The proportions of the taxonomic classification of the bacterial sequences to the classification levels of class, order and genus were 98.4%, 83.2%, and 44.4%, respectively; the proportions of the archaeal taxonomy annotations to the class, order, and genus classification levels were relatively low, being 94.9%, 2.4% and 9.7% respectively.2. Analysis of prokaryotic microbial community structure in different spatial soils.High-throughput sequencing and qPCR results indicated that α diversity of soil bacterial community was higher than that of soil archaeal community. At the same time, the abundance of bacterial 16srRNA gene (1.5×109~4.5×1011) in the soil was higher than that (8.5×106~1.7×109) of the soil archaea. The correlation analysis results between bacterial, archaeal community structure, and environmental factors show that soil physical and chemical properties have more significant effects on bacterial and archaeal community structure. Soil pH affect the soil bacterial and archaeal community structure, and the prokaryotic microbial 16srRNA gene abundance is also affected by soil pH. The secondary influencing factor of the soil bacterial and archaeal community structure is soil organic matter.3. Analysis of prokaryotic microbial community structure in different habitats.Combined PCoA analysis result for soil prokaryotic microorganisms community structure with vegetation types in Tibetan Plateau, the sample plot can be divided into three habitats: alpine meadow, alpine grassland, and desertification grassland. The results of ANOVA showed that α diversity and richness of the bacterial community in alpine meadow soil was significantly lower than that in alpine grassland and desertification grassland, while the bacterial 16srRNA gene abundance was significantly higher in alpine meadows (P<0.001). There was no significant difference in the α diversity of archaeal community structure among the three habitats, and the 16srRNA gene abundance of archaea was relatively high in relatively poor alpine grassland and desertification grassland (P<0.001). The community composition of soil bacteria and archaea was also different in three different habitats (P<0.01).The correlation analysis between soil physicochemical characteristics and soil prokaryotic microbial community structure in three different habitats showed that, soil physicochemical characteristics were significantly different in different habitats, and different soil physicochemical properties caused the changes of soil prokaryotic microbial community and abundance (P<0.01). In alpine meadows, soil pH drives the diversity of soil prokaryotic microbial community and soil prokaryotic microbial community structure is mainly limited by soil nutrient elements in high-cold grasslands and desertification grasslands.
|热依汗古丽·吾买尔. 青藏高原土壤中原核微生物群落结构及其空间分布特征研究[D]. 兰州. 兰州大学,2018.|
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