羽毛针禾(Stipagrostis pennata)根鞘中可培养细菌多样性
收稿日期: 2015-10-14
修回日期: 2015-11-23
网络出版日期: 2016-05-20
基金资助
新疆维吾尔自治区杰出青-科技人才培养项目(2013711013);国家自然科学基金项目(41271281,U1203301,41571256)
Culture-dependent Bacteria Diversity in Rhizosheath of Stipagrostis pennata
Received date: 2015-10-14
Revised date: 2015-11-23
Online published: 2016-05-20
羽毛针禾(Stipagrostis pennata)是古尔班通古特沙漠流动沙丘的先锋植物。野生羽毛针禾能够形成特殊的根鞘结构。作为浅根系植物对高温、缺水恶劣环境的特殊应答结构,根鞘对羽毛针禾忍耐干旱胁迫尤为重要。土壤微生物是影响根鞘形成和稳固程度的重要因素,基于前期对羽毛针禾根鞘微生物数量分布特征的分析结果,结合选择性培养基分离纯化、16S rDNA序列测序、Biolog-Eco技术更进一步地分析了可培养细菌多样性特征。结果表明:(1)基于Ribosomal Database Project (RDP)classifier分析,分离、纯化的17株菌可初步归为3门5纲5目8科8属,未见新属。其中,芽孢杆菌属(Bacillus)占绝对优势(23.53%)。(2)EzTaxon-e数据库中对各菌株序列进行进一步的blast同源性分析表明,17株菌可进一步归为13个OTUs,未见疑似新种(同源性均>97%),其中芽孢杆菌属OTU比例仍然最高(23.08%)。(3)根鞘中的土壤细菌群落代谢活性、土壤细菌群落多样性指数(Shannon指数及McIntosh指数)、可培养细菌对糖类、氨基酸类等各类碳源的利用率均显著高于外围土壤。独特的微生物类群是影响根鞘形成的重要外部因素,其与根系分泌物的互动关系值得深入研究。
吴楠 , 史应武 , 朱秉坚 , 张元明 . 羽毛针禾(Stipagrostis pennata)根鞘中可培养细菌多样性[J]. 中国沙漠, 2016 , 36(3) : 718 -725 . DOI: 10.7522/j.issn.1000-694X.2015.00177
Stipagrostis pennata is a typical pioneer psammophyte species distribute in deserts of the Junggar Basin in Northern Xinjiang. This psammophyte is resistant to high temperatures, drought, and sandstorms. The presence of rhizosheath makes its ecological function stronger. Rhizosheaths are structures composed of mucilage secreted from plants and adherent soil microbes that form a hard sand cylinder around the root. Our previous study showed that rhizosheath microhabitats were favorable environment for the growth and development of microorganisms. This study focused on investigating the special microbial diversity in the rhizosheath microhabitats. The results showed that: (1) Using three different medium, 17 strains were isolated from rhizosheath microhabitats. Phylogenetic analysis of partia1 16S rDNA sequences showed that these strains clustered into 3 phyla, 5 classes, 5 orders, 8 families and 8 genera via Ribosomal Database Project (RDP) classifier. The dominant genera were Bacillus (23.53%). (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 13 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 belonged to the genus Bacillus(23.08%). (3) Biological Eco technology showed that both the microbial metabolic activity and diversity were higher in the rhizosheaths than that of surrounding soil. It implied that bacteria in the rhizosheaths could well use the carbon substrates. To further discuss the relationship between the exudation from the plant and microbe, we will further investigate not only the influence of root exudation on the growth of dominant species of the microbe in the rhizosheaths, but also their soil binding properties, their mix-effect to the character of rhizosheaths.
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