摘要:以宁夏贺兰山东麓荒漠藻结皮为研究对象，对处于不同发育阶段的藻结皮中微生物群落结构及其演替进行了研究。结皮样品高通量测序结果分别得到521个16S rDNA序列操作分类单元（OTU）和64个18S rDNA序列OTU，表明藻结皮中原核微生物多样性远高于真核微生物；贺兰山东麓藻结皮中原核微生物分布于26个纲，Cyanobacteria在各个发育阶段中都是优势微生物类群，Actinobacteria、Chloroplast、Alphaproteobacteria和Bacilli在藻结皮发育的各个阶段相对丰度也较高；从属水平上分析，Bacillus、Leptolyngbya、Microcoleus、Microvirga、Chroococcidiopsis、Rubellimicrobium、Phormidium、Mastigocladopsis、Skermanella、Nostoc、Scytonema共11个属在各个发育阶段的藻结皮中都存在，只是出现了丰度的差异。Bacillus在藻结皮形成期、发育初期和发育中期相对丰度较大，成熟期丰度显著下降，而成熟期Microvirga丰度较前3个时期显著增加，表现出明显的细菌菌群演替现象。藻结皮样品中主要真核微生物分布于13个纲，其中Dothideomycetes和Pezizomycetes在各个发育阶段样品中丰度都很高，Agaricomycetes在形成期样品中相对丰度高达32.6%，但在藻结皮发育过程中其相对丰度迅速下降；原生生物的相对丰度在藻结皮发育过程中逐渐增加；4个发育阶段藻结皮样品中均未检测到真核微藻序列。4个发育阶段的藻结皮样品中有明确分类学信息的真核微生物共13个属，其中4个发育阶段中共有的为Coniothyrium、Dendryphion、Friedmanniomyces、Phloeopeccania、Sarocladium共5个属，其余8个属只在个别发育阶段样品中检出，表明在藻结皮发育过程中真核微生物的群落结构也发生着变化。藻结皮厚度、全氮含量及有机质含量是影响结皮层微生物群落组成的主要因素。



Abstract:In this paper, algal crusts collected from desert soil of the east side of the Helan Mountain were used as samples to study the microbial communities and their succession during early development of biological soil crusts. 521 16S rDNA OTUs and 64 18S rDNA OTUs were obtained from all samples via high throughput sequencing, which showed that diversity of prokaryotes was obviously higher than that of eukaryotic microorganisms. Prokaryotes in algal crusts were distributed in 26 classes. Cyanobacteria was the dominant microbial group in 4 development stages samples. Actinobacteria, Chloroplast, Alphaproteobacteria, and Bacilli were also higher relative abundance in all stages of samples. In the taxonomic level of genera, Bacillus, Leptolyngbya, Microcoleus, Microvirga, Chroococcidiopsis, Rubellimicrobium, Phormidium, Mastigocladopsis, Skermanella, Nostoc, and Scytonema existed in all stages of samples, but the abundance of each of them were different. The relative abundance of Bacillus was higher in the formation stage, initial stage, and intermediate stage samples, but decreased significantly in maturity stage samples. On the contrary, the relative abundance of Microvirga increased significantly in maturity stage samples. The above results indicated that there was obvious succession of bacterial communities. Eukaryotic microorganisms in samples were distributed in 13 classes. The abundance of Dothideomycetes and Pezizomycetes were higher in all stages samples. The abundance of Agaricomycetes was as high as 32.6% in formation stage, however, its abundance was declined rapidly in the development process of algal crusts. The abundance of protists increased gradually with development of algal crusts. No sequence of eukaryotic microalgae was found in all stages of samples. Thirteen genera of eukaryotic microorganisms which had taxonomic information were found in samples. In which, Coniothyrium, Dendryphion, Friedmanniomyces, Phloeopeccania, and Sarocladium occurred in all stages samples, and the rests occurred only in individual stage samples. The results showed that the eukaryotic microorganisms community also had been changing with the development of algal crusts. The main factors on microbial community were thickness, total nitrogen and organic maters of crusts.





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