芒草种植对土壤细菌群落结构和功能的影响

Effect of Miscanthus planting on the structure and function of soil bacterial community

芒草作为第二代能源植物的代表,其生长过程中根际土壤细菌群落的结构与功能尚不清楚.本研究以种植5年的芒草(湘杂芒1号)为研究对象,选取裸地作为对照,采用16S rRNA基因Miseq测序技术研究其细菌群落组成,同时采用PICRUSt功能预测分析其功能.结果表明:芒草根际细菌由变形菌门、酸杆菌门、放线菌门、绿弯菌门、拟杆菌门和芽单胞菌门等23个门、231个属的细菌组成,表现出群落组成的丰富性.细菌群落分析表明,种植湘杂芒1号改变了根际细菌群落结构,其细菌群落多样性低于裸地对照.PICRUSt功能预测分析表明,湘杂芒1号根际细菌主要涉及氨基酸运输和代谢、细胞壁/细胞膜/膜结构的生物合成、信号转导机制等24个基因功能家族,表现出功能上的丰富性,并有22个基因功能家族预测基因相对丰度高于裸地,表明种植湘杂芒1号提高了根际细菌功能.对氮、磷循环相关基因进行分析表明,种植湘杂芒1号改变了土壤氮、磷代谢能力.

Miscanthus is a promising candidate species of second-generation energy crops.To our knowledge,the composition and function of Miscanthus rhizosphere bacterial communities has not yet been reported.In this study,rhizosphere soil samples were collected from Miscanthus(Xiangzamang No.1)which was grown in Nanyang City for five years and bareground(as the control)to analyze the bacterial community structure and diversity using 16 S rRNA gene sequencing on the Illumina MiSeq platform.PICRUSt was used to determine the metabolic and functional abilities of soil bacterial communities.Phylogenetic analysis based on 16S rRNA gene sequences showed that sol bacteria could be divided into 23 phyla and 231 genera,with high richness of the community composition.The dominant phyla were Proteobacteria,Acidobacteria,Actinobacteria,Chloroflexi,Bacteroidetes and Gemmatimonadetes.The bacterial community diversity in the rhizosphere samples of Xiangzamang No.1 was lower than that in unplanted samples.Rhizosphere bacterial communities were affected by Miscanthus crops.Based on the PICRUSt analysis of bacterial community functions,our results revealed a wide genetic diversity of organisms involved in various essential processes,such as amino acid transport and metabolism,cell wall/membrane/envelope biogenesis,signal transduction mechanisms.Based on the 16S rRNA gene copy number of the detected phylotypes,22 bacterial metabolic function in the rhizosphere samples of Miscanthus was higher than that in bareground.Results from N-and P-cycling gene analysis showed that Miscanthus planting altered the N-and P-cycling metabolic capacities of soil bacteria.