尽管细菌的锰氧化作用被认为是自然界中氧化锰矿物形成的主要成因,但目前国内外对陆地土壤环境中锰氧化细菌的种群组成与多样性方面的研究甚少.本研究对采集于山东崅峪一处含铁锰结核的棕壤进行了可培养锰氧化细菌分离、活性测定与多样性调查,结果发现表层土壤(A层:0～20 cm)的可培养锰氧化细菌是最丰富的,但是高锰氧化活性的细菌主要分布在心土层(B层:20～40 cm)和底土层(C层:＞75 cm).通过对具有高锰氧化活性的分离菌株16S rRNA基因的扩增、测序和序列BLAST比对分析,发现了7个此前未见报道的具有锰氧化活性的新随属.此外,对5株具有高锰氧化活性的分离菌株和土壤样品的进行了16S rRNA基因V3产物的变性梯度凝胶电泳(DGGE)分析,结果显示此5株高锰氧化菌株并非都是土壤中的高丰度细菌.%Although Mn(Ⅱ)-oxidizing bacteria are generally regarded as the major contributors of naturally occurred manganese oxides, only little effort has been devoted to investigate the community composition and diversity of Mn(Ⅱ)-oxidizing bacteria in the terrestrial soil environment so far. In the current study, the stratified soils with iron-manganese nodules were sampled to isolate the culturable Mn(Ⅱ)-oxidizing bacteria and to determine their Mn(Ⅱ)-oxidizing activities as well as to identify their community diversity. The results showed that most cultivable Mn(Ⅱ)-oxidizing bacteria occurred in the A-horizon (0-20 cm) soil, whereas most Mn(Ⅱ)-oxidizing bacteria with high activities occurred in B- (20-40 cm) and C-horizon (>75 cm) soils. 7 novel Mn(Ⅱ)-oxidizing bacterial genera were found in this study from the isolates with high Mn(Ⅱ)-oxidizing activity through 16S rRNA gene sequencing and related phylogenetical affiliation analysis. Moreover, PCR-DGGE profiles revealed that five randomly selected high Mn(Ⅱ)-oxidizing bacteria were not abundant in the corresponding soil, which provided an insight of possible relationship between Mn(Ⅱ)-oxidizing bacteria and their survival soil environment.
展开▼
