石油污染对芦苇根际细菌群落组成和多样性的影响

Effect of petroleum pollution on the composition and diversity of bacterial community in Phragmites australis rhizosphere

为探究石油污染对植物根际细菌群落组成和多样性的影响,完善植物根际微生物在维持根系固土能力及恢复水土调控技术,以扎龙湿地芦苇种群的原位土壤为材料,模拟轻度(3 g/kg)、中度(6 g/kg)、重度(12 g/kg)的石油污染,采用盆栽的方式培养芦苇根茎60 d,利用土壤分析仪测定土壤理化性质,利用高通量测序技术分析芦苇根际土壤细菌的群落丰度和组成。结果表明:石油污染显著提高(P<0.05)土壤中铵态氮、速效磷和有机质的含量,使其分别上升41%、121%、141%,而对土壤pH和有效钾含量无显著影响(P>0.05);芦苇根际土壤中细菌包含33门111属,其中Proteobacteria占37.31%~46.6%,为优势菌群;优势菌属(相对丰度>1%)共计23种,其中Pseudomonas和Hydrogenophaga是优势菌属,对石油污染有良好适应性。轻度石油污染根际土壤中细菌多样性最低,重度污染根际土壤中细菌多样性最高。石油污染促进Pseudomonas和Hydrogenophaga的生长,抑制Exiguobacterium、Rhodoligotrophos、Citrobacter、Aridibacter、Azoarcus、Gp21、Mongoliicoccus的生长。石油污染改变土壤营养物质含量,对芦苇根际土壤细菌群落结构和多样性产生显著影响。

[Background]Petroleum pollution caused by accidents in petroleum production and transportation will change soil physical and chemical properties,resulting in soil erosion and serious damage to the ecological environment.Phragmites australis is a plant with strong stress resistance,which often is used as a plant material for ecological restoration.It plays an important role in resistance to stress through interaction with rhizosphere bacterial community.Petroleum pollution has a significant influence on the structure and diversity of rhizosphere bacterial community,which may be one of the important factors hindering the growth and development of P.australis in petroleum contaminated soil.[Methods]In order to reveal the effects of different concentrations of petroleum pollution on soil and rhizosphere bacterial community of P.australis,soil samples and P.australis rhizomes were collected from Zhalong wetland.P.australis rhizomes planted in soil which had used to simulate mild(3 g/kg),moderate(6 g/kg),and severe(12 g/kg)petroleum pollution.Cultured for 60 d,then soil ammonium nitrogen,available phosphorus,available potassium,and organic matter were measured.The community abundance and composition of the P.australis rhizosphere bacteria under different soil petroleum treatments were detected by high-throughput sequencing and bioinformatics method.[Results]Petroleum pollution significantly increased the content of ammonium nitrogen,available phosphorus and organic matter in soil,respectively by 41%,121%and 141%,but had no significant effect on soil pH value and available potassium.The high-throughput sequencing showed that P.australis rhizosphere soil contained 33 phyla and 111 genera of bacteria,of which Proteobacteria was the dominant bacterium with a proportion from 37.31%-46.6%.There were 23 genera of dominant bacteria(relative abundance>1%),of which Pseudomonas and Hydrogenophaga was the dominant genus that demonstrated good adaptability to petroleum pollution.The bacteria diversity was the lowest in the slight polluted soil,and the highest in the severe polluted soil.Petroleum pollution promoted the growth of Pseudomonas and Hydrogenophaga,and inhibited the growth of Exiguobacterium,Rhodoligotrophos,Citrobacter,Aridibacter,Azoarcus,Gp21,and Mongoliicoccus.Slight petroleum pollution promoted the growth of Desulfuromonas and Bellilinea,and high petroleum pollution inhibits its growth.[Conculsions]Petroleum pollution changed soil nutrient content and had a significant effect on bacterial community structure and diversity in the rhizosphere soil of P.australis.