不同月份沙棘根瘤细菌群落结构特征的分析对比

为深入了解沙棘（Hippophae rhamnoides）根瘤细菌的多样性及其随时间变化，采用高通量测序技术对中国沙棘（H.rhamnoides subsp. sinensis）4个不同月份根瘤细菌群落结构特征进行了分析对比。结果表明，在根瘤瘤瓣刚刚开始萌发的3月，沙棘根瘤细菌的多样性和丰富度显著高于5、7月和8月。4个采样时间所获得的根瘤细菌可归类为21门36纲75目145科234属，其中有8菌门的17菌纲在不同采样时间一直存在。从相对丰度来看，放线菌门放线菌纲（Actinobacteria）始终为优势菌纲，其相对丰度3月为65.30%，5、7月和8月均超过96.05%；同时，根瘤细菌中还存在变形菌门的α-、β-和γ-变形菌纲（Alpha-,Beta-,Gammaproteobacteria）以及拟杆菌门噬纤维菌纲（Cytophagia）和鞘脂杆菌纲（Sphingobacteriia）等多种类型的非放线菌。弗兰克氏菌目（Frankiales）细菌在整体根瘤细菌群落中的相对丰度3月为48.60%，显著低于5月的93.54%、7月的95.48%和8月的94.73%；4个采样时间共获得5科6属10条可操作分类单元（operational taxonomic units，OTUs），其中弗兰克氏菌科（Frankiaceae）弗兰克氏菌属（Frankia）的OTU235占该目的相对丰度在不同时间均在99%。表明沙棘根瘤细菌群落在不同月份均是极其丰富和多样的，其中既有多种类型的放线菌也有多种类型的非放线菌，但均以弗兰克氏菌科弗兰克氏菌属细菌占绝对优势；同时，根瘤细菌群落结构（特别是弗兰克氏菌的相对丰度）随季节发生着显著变化。

Comparison of the Characteristics of Bacterial Community in Root Nodules of Hippophae rhamnoides in Different Months

In order to deeply understand the diversity and time variations of Hippophae rhamnoides root nodule bacteria (RNB),the characteristics of bacterial community of the nodules of H.rhamnoides subsp.sinensis in four different months were analyzed and compared by using high-throughput sequencing technology.The results showed that the diversity and the richness of the RNB in March when the new root nodules just germinated were significantly higher than those in May,July and August.The bacteria obtained from the nodules in four sampling time could be classified into 21 phyla,36 classes,75 orders,145 families,and 234 genera.Among them,17 classes of 8 phyla were found all the time.From the view of relative abundance,Actinobacteria was always the dominant class,65.30% in March,and over 96.05% in May,July and August.Many types of non-actinomycetes,such as the Alpha-,Beta-and Gamma-proteobacteria of the phylum Proteobacteria as well as Cytophagia and Sphingobacteriia of the phylum Bacteroidetes also presented.In March,the relative abundance of Frankiales in the whole bacterial community was 48.60%,which was significantly lower than those in May (93.54%),July (95.48%) and August (94.73%).A total of 10 operational taxonomic units (OTUs) belonging to 6 genera of 5 families of Frankiales were obtained,in which OTU235 belonging to the genus Frankia always remained a relative abundance of about 99% in all of the sampling time.In summary,the community of H.rhamnoides RNB in different months was extremely rich and diverse,including many types of actinomycetes and non-actinomycetes.Frankia always was the dominate genus.And the bacterial community structure (especially the relative abundance of Frankia) of nodules changed significantly with seasons.