纳帕海农田土壤氨氧化细菌的群落结构

Ammonia Oxidizing Bacteria Community Structure in Napahai Farmland Soil

为弄清不同季节纳帕海农田土壤氨氧化细菌群落结构的变化特征,选取代表性农田于干季和湿季采用梅花点法选取上(0~20cm)、下(20~40cm)两层土壤,结合环境因子探讨其对氨氧化细菌群落结构的影响。提取土壤总DNA,对amoA基因进行特异性扩增和高通量测序,并结合冗余分析法分析氨氧化细菌群落结构组成、丰度及其与土壤环境因子的关系,确定主要环境因子。结果表明:农田土壤有机质、全氮、水解性氮、速效磷、速效钾及硝态氮含量在湿季上层土壤中均最高,分别为70.79g/kg、2.90g/kg、389.04mg/kg、78.84mg/kg、768.92mg/kg和49.04mg/kg;干季上层土壤全磷和全钾含量为最高,分别为1.33g/kg和15.13g/kg。经高通量测序,亚硝化螺菌属(Nitrosospira)为农田土壤氨氧化细菌的优势菌属,Nitrosospira-sp.-Nsp2和uncultured-Nitrosospira-sp.为主要优势氨氧化细菌,土壤氨氧化细菌多样性表现为干季上层>湿季上层>湿季下层>干季下层。结合冗余分析,影响干季农田上层土壤氨氧化细菌群落结构的主要环境因子及影响程度分别为速效磷>全氮>亚硝态氮,对于干季下层土壤则是铵态氮>亚硝态氮>全钾>硝态氮>全磷;湿季土壤氨氧化细菌群落结构明显受多种环境因子的综合影响。

In order to explore the variation characteristics of ammonia oxidizing bacteria community structure in Napahai farmland soil in different season, soil samples were collected by plum point method in upper（0-20 cm） and lower（20-40 cm） soil layers in representative farmlands in dry and wet seasons, and the effects on ammonia oxidizing bacteria community structure were explored combined with soil environmental factors. High-throughput sequencing technique and redundancy analysis method were used to analyze the relationship among environmental factors and these ammonia oxidizing bacterial community structure based-on amoA gene from soil total DNA, and to determine the main environmental factors. Results. Contents of organic matter, total nitrogen, hydrolysable nitrogen, rapidly available phosphorus, rapidly available K, and nitrate nitrogen are the highest in upper soil in wet season, respectively 70.79 g/ kg, 2.90 g/kg, 389.04 mg/kg, 78.84 mg/kg, 768.92 mg/kg, 49.04 mg/kg. In dry season, the upper farmland soil has the highest content of total phosphorus and total K, respectively 1.33 g/kg and 15.13 g/ kg. By high throughput sequencing, Nitrosospira-sp.-Nsp2 and uncultured-Nitrosospira-sp, are mainly the dominant ammonia oxidation bacteria, belongs to the Nitrosospira at genus level. The diversity of ammonia oxidation bacteria shows that the upper soil in dry season〉 the upper soil in wet season〉 the lower soil in wet season〉 the lower soil in dry season. Known from the analysis of redundancy, the mainly environmental factors affect the upper farmland soil ammonia oxidizing bacteria in dry season shows the rule of rapidly available phosphorus〉 total nitrogen〉 nitrite nitrogen, for the lower soil in dry season is ammonium nitrogen 〉nitrite nitrogen〉 total K 〉 nitrate nitrogen〉 total phosphorus. The soil ammonia oxidizing bacteria community structure in wet season is obviously affected by multiple environmental factors.