有机肥施加对红壤中反硝化细菌nirK基因多样性影响

为了解有机肥施用对于红壤中反硝化细菌群落结构的影响,设置了4个处理:CK(不施肥)、LM(低量有机肥)、ML(高量有机肥+石灰)和HM(高量有机肥)进行研究,并通过末端限制性片段长度多态性(T-RFLP)和克隆文库的DNA测序估计了nirK基因的多样性。结果表明:各处理分别挑选的288个阳性克隆子可分为78个类型,各处理nirK文库中的优势类群属于同一种类型,在CK处理中的占比为51%,在其他3个处理中的占比依次为33%、32%和27%。4个文库之间两两的相似性在37.50%~45.34%,系统进化树分析表明,51个OTUs测序结果中6个OTUs与苍白杆菌属的相似性最高,占测序总数的11.8%;其余45个OTUs属于未培养类型,占测序总数的88.2%。有机肥添加有助于提高nirK基因的多样性,并且出现了红壤原始环境中未出现的反硝化细菌类型。

Effect of Organic Manure Application on Diversity of nirK Gene in Denitrifying Bacteria in Red Soil

In order to understand the effect of organic manure application on the structure of denitrifying bacteria in red soil, four treatments were designed and compared:1) CK, no manure; 2) LM, low organic manure; 3) ML, high organic manure + lime; and 4) HM, high amount organic manure. The diversity of the nirK gene was estimated by terminal restriction fragment length polymorphism (T-RFLP) and DNA sequencing of the cloned library. The results showed that the 288 clones selected in each treatment can be divided into 78 clusters, and the dominant groups in each nirK library were of the same cluster, accounting for 51% of the CK, while the other three treatments were 33%, 32% and 27%, respectively. The similarity between the four libraries was between 37.50% and 45.34%. The phylogenetic tre e analysis of the 51 OTUs showed that 6 OTUs had the highest similarity with Ochrobactrum sp., accounting for 11.8% of the total number of sequencing. The remaining 45 OTUs belonged to the uncultured cluster, accounting for 88.2% of the total number of sequencing. Organic manure addition increased the diversity of the nirK gene, but some types of denitrifying bacteria didn''t appear in the original red soil environment.