塔克拉玛干沙漠腹地胡杨林土壤细菌多样性分析

【目的】对塔克拉玛干沙漠腹地胡杨林土壤细菌多样性进行初步探索,为下一步从中筛选可用于生物饲料或生物肥料的微生物奠定基础。【方法】采用可培养方法,进行细菌的分离纯化。对各菌株进行革兰氏染色及淀粉酶、酯酶、纤维素酶和NaCl耐受浓度的测定,并提取各菌株基因组DNA,进行16SrRNA基因扩增、测序及系统进化树的绘制,分析其多样性。【结果】共分离得到27株菌,其中放线菌门(Actinobacteria)16株,变形菌门(Proteobacteria)4株,厚壁菌门(Firmicutes)6株,拟杆菌门(Bacteroidetes)1株。革兰氏染色结果表明,5株菌为革兰氏阴性,其余为革兰氏阳性;酶活测定结果表明,15株菌具有淀粉酶活性,9株菌具有酯酶活性,9株菌具有纤维素酶活性;NaCl耐受浓度测定结果显示,NaCl浓度为2%时所有菌株均能生长,5%时能生长的有22株,15%时能生长的有1株。【结论】塔克拉玛干沙漠腹地胡杨林土壤中存在较丰富的细菌类群,且具有一定的酶学活性和NaCl耐受性,具有进一步研究开发的价值。

Bacteria diversity of soil of Populus Euphratica Forest in the hinterland of Taklimakan Desert

Abstract: Objective] The aim of study was to investigate bacterial diversity of Populus Euphratica forest in the hinterland of Taklimakan desert. All the isolateds were be used as inoculants for silage and biofertilizer. Methods] Strains were isolated by culture-dependent method. Gram staining, NaCl tolerance, enzyme activity (including amylase, esterase, cellulase) were determined by strand methods. Phylogenetic trees based on 16S rRNA gene sequences were constructed by using the neighbour-joining. Results] A total of 27 strains were obtained. Phylogenetic analysis of the bacterial 16S rRNA gene showed that all isolates fell into one of the following four bacterial lineages: Actinobacteria(16 strains), Proteobacteria(4 strains), Firmicutes(6 strains) and Bacteroidetes(1 strains). Gram staining indicated that 5 strains were gram-negative and the others were gram-positive. Among these, 15 strains showed amylase activity, 9 strains showed esterase activity and 9 strains showed cellulase activity. All strains growth occurred at in presence of 2% NaCl, 22 strains growth occurred at in presence of 5% NaCl and only 1 strain tolerated up to 15% NaCl. Conclusion] The bacterial population diversity is abundant in soil of Populus Euphratica Forest in the hinterland of Taklimakan Desert, which is worthy of futher investigation.