基于克隆文库法研究古尔班通古特沙漠蓝藻多样性

Cyanobacterial Diversity of Gurbantunggut Desert Based on Clone Library,Xinjiang,China

该研究采用克隆文库法研究古尔班通古特沙漠藻类生物结皮中蓝藻多样性及分布。在古尔班通古特沙漠不同区域采集10份藻类结皮代表性土样,分别构建古尔班通古特沙漠蓝藻16S rRNA和psbA基因克隆文库,并进行系统发育分析,对蓝藻多样性和丰度与环境因子进行关联分析,研究蓝藻分布特点及影响因子。结果显示:(1)16S rRNA基因系统发育树中包括具有明确分类地位的蓝藻有6科10属(占总克隆文库的94.85%)和一个未分类蓝藻属,其中颤藻属(Oscillatoria)和微鞘藻属(Microcoleus)分别占克隆文库的42.54%和37.16%,为古尔班通古特沙漠蓝藻优势属;psbA基因系统发育树中仅鉴定有蓝藻类群4科4属,但优势属与前者结果一致。(2)10个样点藻类结皮中所含蓝藻种类不尽相同,但每个采样点都出现颤藻属和微鞘藻属,证明这二者是古尔班通古特沙漠藻类结皮中的优势属;且样点Gur2和Gur17中蓝藻种类较多,Gur3、Gur5和Gur9中种类较少,但Gur2、Gur3、Gur5和Gur17相对地理位置较近,表明地理位置不是影响蓝藻分布的主要因素。(3)RDA(Redundancy analysis)分析结果显示,微生物量氮(MBN)和土壤有机碳(SOC)对蓝藻多样性影响程度最大,其次是硝态氮(NO-3-N)、微生物量碳(MBC),全磷(TP)和全钾(TK)对其影响程度最小。研究表明,古尔班通古特沙漠不同区域沙漠蓝藻多样性和土壤理化性质具有空间异质性,综合分析可得沙漠中南部藻类结皮土壤营养最为丰富,蓝藻多样性较高,而东部和西部土壤营养较为贫瘠,蓝藻丰富度和多样性较低。

The goal of this study was to research the cyanobacterial diversity and distribution in algal crusts of Gurbantunggut Desert by the clone library method.In this paper,10 representative algal crust soil samples were collected in different regions of the Gurbantunggut Desert,and the cyanobacterial 16S rRNA and psbA gene clone libraries were constructed and performed phylogenetic analysis.Moreover,the correlation of cyanobacterial diversity and abundance with environmental factors was analyzed to acquire the distribution characteristics and influencing factors of cyanobacteria.The results showed:(1)the cyanobacterial 16S rRNA gene belonged to 10 genera of 6 families(accounted for 94.85%of the total library)and an uncultured cyanobacteria by phylogenetic analysis.Oscillatoria and Microcoleus accounted for 42.54%and 37.16%of the library respectively,which were the dominant genus of cyanobacteria in Gurbantunggut desert.Only 4 genera of 4 families cyanobacteria were identified with the psbA gene by phylogenetic analysis,but the dominant genera were consistent with the former results.(2)The species of cyanobacteria in algal crusts were different from each other in the 10 sample sites,but Oscillatoria and Microcoleus were found in each sample site,which proved that they were the dominant genera in algal crusts of Gurbantunggut Desert.In addition,there were more cyanobacteria species in Gur2 and Gur17,and fewer cyanobacteria species in Gur3,Gur5 and Gur9.However,the relative geographical locations of Gur2,Gur3,Gur5 and Gur17 were relatively close,indicating that geographical location was not the main factor affecting the distribution of cyanobacteria.(3)Redundancy analysis results showed that microbial biomass nitrogen(MBN)and soil organic carbon(SOC)have the greatest impact on the diversity of cyanobacteria,followed by nitrate nitrogen(NO-3-N),microbial biomass carbon(MBC).Total phosphorus(TP)and total potassium(TK)have the least impact.The research showed that the cyanobacteria diversity and physicochemical properties of the soil in different regions of the Gurbantunggut Desert are spatially heterogeneous.The algae crusts in the middle,south of the desert are the most nutritious and the diversity of cyanobacteria is higher,while the algae crusts in the east,west are poor in nutrition,and the cyanobacteria richness and diversity are lower.