基于高通量测序的准噶尔盆地荒漠土壤细菌多样性及群落结构特征

荒漠草地占新疆草地总面积的46.9%,不同荒漠类型的气候差异显著,植被和土壤类型也各不相同。以准噶尔盆地大面积分布的3种代表性荒漠植被类型(南缘伊犁绢蒿荒漠、腹地白梭梭荒漠和北缘盐生假木贼荒漠)为研究对象,应用高通量测序技术,分析比较3种荒漠植被类型的土壤细菌群落组成和多样性特征。结果表明:放线菌门、变形菌门、绿弯菌门、酸杆菌门、芽单胞菌门和拟杆菌门是准噶尔盆地荒漠土壤中6个主要优势类群细菌,其相对丰度累计超过94%。放线菌门在3种荒漠类型中相对丰度最高,均超过50%,但差异不显著(P>0.05);酸杆菌门在伊犁绢蒿荒漠中相对丰度最高,厚壁菌门在白梭梭荒漠丰度最高,拟杆菌门在盐生假木贼荒漠丰度最高,且这3种菌门在3种荒漠类型中差异显著(P<0.05);在3种荒漠类型中,白梭梭荒漠细菌操作分类单元(OTU)数最少,多样性最低。Pearson相关性分析和RDA分析结果均表明,年均降水量和土壤有机碳是影响细菌群落结构组成和多样性最显著的环境因子。

A high-throughput sequencing evaluation of bacterial diversity and community structure of the desert soil in the Junggar Basin

Desert grassland accounts for 46.9% of the total grassland area in Xinjiang, with different desert types in areas of different climate, each with significantly different vegetation and soil types. Three representative desert vegetation types: Seriphidium transiliense desert in the southern margin, Haloxylon persicum desert in the hinterland and Anabasis salsa desert in the northern margin of the Junggar Basin, were chosen for study. The bacterial community composition and diversity characteristics of the three desert vegetation types were analyzed and compared using a high-throughput sequencing technique. It was found that Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria, Gemmatimonadetes, and Bacteroidetes were the six dominant groups of bacteria in these Junggar Basin soils. The cumulative abundance was more than 94%. Actinobacteria had the highest relative abundance (>50%) in all three desert types, and the difference between desert types for relative abundance of Actinobacteria was not significant (P>0.05). Acidobacteria had a relative abundance in S. transiliense desert notably higher than in other desert types, while Firmicutes bundance was higher in H. persicum desert than in other desert types, and Bacteroidetes had the highest relative abundance in A. salsa desert, and these differences were significant (P<0.05). Among the three desert types, the number of bacterial operational taxonomic units in H. persicum desert was the lowest and the community diversity was the lowest. Pearson correlation and redundancy analyses showed that average annual precipitation and soil organic carbon are the most significant environmental factors affecting the composition and diversity of the bacterial communities studied.