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干旱区地理 ›› 2014, Vol. 37 ›› Issue (2): 250-258.

• 生物与土壤 • 上一篇    下一篇

古尔班通古特沙漠苔藓结皮中可培养细菌多样性特征

吴楠1,张元明1,潘惠霞1,邱东2   

  1. (1    中国科学院干旱区生物地理与生物资源重点实验室,中国科学院新疆生态与地理研究所, 新疆    乌鲁木齐    830011;
    2    新疆农业大学 草业与环境科学学院, 新疆    乌鲁木齐    830052)
  • 收稿日期:2013-08-01 修回日期:2013-10-20 出版日期:2014-03-25
  • 通讯作者: 张元明. Email:zhangym@ms.xjb.ac.cn
  • 作者简介:吴楠(1980-),女,新疆石河子市人,博士,副研究员,主要从事荒漠植物-微生物互作研究. Email:wunan@ms.xjb.ac.cn
  • 基金资助:

    新疆维吾尔自治区科学基金青年基金项目(2009211B31“古尔班通古特沙漠南缘藻结皮及地衣结皮固氮潜能探析”)

Culture-dependent bacteria diversity of moss crusts in the Gurbantunggut Desert

WU  Nan1,ZHANG  Yuan-ming1,PAN  Hui-xia1,QIU  Dong2   

  1. (1   Key Laboratory of Biogeography and Bioresource in Arid land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi  830011,Xinjiang, China;   2   College of  Pratacultural and  Environmental Science, Xinjiang Agricultural University, Urumqi  830052, Xinjiang, China)
  • Received:2013-08-01 Revised:2013-10-20 Online:2014-03-25

摘要: 在不同类型的生物土壤结皮中,苔藓结皮蓄水能力、抗机械干扰和固沙的能力最强,在受损沙地的人工修复中发挥着更为重要的生态作用。通过挖掘具固氮、固沙等功能的重要菌株资源可改善苔藓结皮的土壤结构、增强苔藓植物抗旱性、提高苔藓生长。前期工作中发现集中分布于垄间低地的苔藓结皮中微生物数量远高于沙垄其它部位的结皮,但究竟是哪些特殊类群的细菌对苔藓结皮的生态功能产生影响尚不清楚。本文对苔藓结皮中数量占绝对优势的细菌多样性进行了进一步的分析,结果表明:(1)分离、纯化的25株菌可初步归为3门3纲4目6科6属,未见新属。其中,芽孢杆菌属(Bacillus)占绝对优势(52%);(2)进一步的blast同源性分析表明,25株菌可归为18个OTUs(Operational Taxonomic Unit),未见疑似新种(同源性均>97%),其中芽孢杆菌属OTU比例最高(39%);(3)将结果与前期工作中地衣结皮可培养细菌多样性进行了对比分析,发现该沙漠苔藓结皮中的可培养细菌Shannon-Wiener多样性指数为2.77,高于地衣结皮(2.55)。这与苔藓结皮具有更强的抗风蚀能力和更高的蓄水能力有关。而硅酸盐细菌在两类结皮中均存在,该类菌株将与苔藓植物协同固沙,推进生物土壤结皮的发育。

关键词: 原核生物, RDP在线归类, EzTaxon-e数据库, Shannon-Wiener多样性指数, 硅酸盐菌株

Abstract: Biological soil crusts,given their extraordinary abilities to survive desiccation and extreme high temperatures,high pH and high salinity,have been found in deserts all over the world.They play a significant role in the process of formation,stability and fertility of soil,prevention of soil erosion caused by wind or water. Comparing to other biological soil crusts (algae crust or lichen crusts),moss crusts play the most significant role in ensuring the proper functioning of desert ecosystem,such as involvement in the process of formation,stability and fertility of soil,prevention of soil erosion caused by wind or water. Our previous research found that the quantity of microbe in the moss crusts was high. However,we had no idea with the diversity of those microbes when we wanted to use them in the sand-fixing application. In order to investigate the relationship between the moss and the microbe around the rhizoid,25 bacterial strains were isolated from moss crusts using three different medium. Phylogenetic analysis of partial 16S rDNA sequences showed as follows:(1) These strains were clustered into 3 phyla,3 classes,4 orders,6 families and 6 genera via Ribosomal Database Project (RDP) classifier. The phyla Proteobacteria,Actinobacteria and Firmicutes respectively owned 2,8,15 of the 25 strains. The dominant genera were Bacillus(52%) and Streptomyces (24%). (2) Further classification of these strains was achieved via Basic Local Alignment Search Tool (BLAST) Homology analysis of the partial 16S rDNA against the EzTaxon-e database. BLAST results yielded 18 Operational Taxonomic Units (OTUs) and no novel species whose sequence similarity was lower than 97% compare to the species in the EzTaxon-e database. Most of these OTUs belong to the genus Bacillus (39%) and Streptomyces(33%). (3) The Shannon-Wiener diversity index of moss crusts was 2.77,the value higher than that of lichen crusts for the same Gurbantunggut Desert. Because that the sand-fixing and water-trapping ability of moss crusts was stronger than that of lichen which would provide suitable habit for more microbe. For example,the leaf hair points of moss were confirmed as a critical part of adaptation to,and survival in,the extremely arid environment of the Gurbantunggut Desert,facilitating the capture of minimal quantities of water (rain,fog and/or dew),increasing the speed at which water could be absorbed into the leaf,and altering the leaf angle to effect optimum photosynthesis and carbon gain. We should pay more attention to the silicate bacterium such as Paenibacillus mucilaginosus which existed in both lichen crusts and moss crusts. It should be note that silicate bacterium could release lots of nutritional ions from soil and exhibited a multifunctional role for sand stabilization and maintenance of water. Although no nitrogen-fixing bacteria strains such as Azotobacter were isolated in this research,our unpublished data based on 454 sequencing techniques showed that the species belong to Rhizobiales was abundant. The complicated mutualistic symbiosis relationship between moss and bacteria in moss crusts would improve the development and ecological function of BSCs.

Key words: prokaryote, Ribosomal Database Project (RDP) classifier, EzTaxon-e database, Shannon-Wiener diversity index, silicate bacterium

中图分类号: 

  • Q939.99