七星河湿地氨氧化古菌多样性和丰度及其与环境因子的相关性分析

以典型东北寒温带沼泽湿地——七星河湿地中芦苇和小叶樟植被下不同深度土壤中氨氧化古菌(Ammonia-Oxidizing Archaea,AOA)为研究对象,以编码氨氧化作用关键酶——氨单加氧酶(AMO)的amo A基因为分子标记,通过构建克隆文库和生物信息学方法分析数据,考察了不同植被环境中AOA多样性和丰度的垂直分布规律,及其与环境因子的相关性.研究结果表明,小叶樟植被土壤中AOA amo A基因多样性显著高于芦苇植被土壤中amo A基因多样性,芦苇植被土壤中AOA amo A基因多样性在深度为40~60 cm土层中最高,AOA多样性与NH+4-N、NO-3-N含量呈正相关;小叶樟植被土壤中AOA amo A基因多样性在深度为20~40 cm土层中最高,AOA多样性与NH+4-N、NO-3-N含量呈正相关.芦苇植被土壤中AOA丰度最低值出现于0~20 cm土层中,到20~40 cm土层中出现最高值,随着深度增加AOA丰度下降,AOA丰度则与NO-2-N含量呈正相关.小叶樟植被土壤中AOA丰度变化趋势与芦苇不同,最高值出现于0~20 cm土层中,随着土层深度增加AOA丰度下降,到40~60 cm出现最低值,AOA丰度与NO-2-N、TOC含量呈正相关.两种植被土壤中AOA丰度均在60~90 cm处有升高趋势.芦苇植被土壤中AOA丰度约是小叶樟植被土壤中AOA丰度的1.49倍.以上结果为湿地AOA生态功能及分布模式的研究提供基础数据,对全球氮循环的研究提供补充.

Diversity and abundance of ammonia-oxidizing archaea and its correlation with environmental factors in Qixing River Wetland

In this study, the vertical variation of the ammonia-oxidizing archaeal (AOA) in the soil of Qixing River wetland, a typical marsh wetland in the cold temperate zone in the northeast China, were investigated. The soil samples were collected under two typical vegetation conditions, Reed (Phragmites australis) and Lobular Camphor (Deyeuxia langsdorffii (Link) Kunth). The clone libraries were built based on the Polymerase Chain Reaction (PCR) products of the AOA amoA gene. The effect of the environmental factors on the AOA community was analyzed with Bioinformatics methods. The result showed the diversity of the AOA amoA gene is higher under the lobular camphor condition than the reed condition. Under the reed condition, the highest AOA amoA gene diversity presented in the depth of 40~60 cm and was significantly positively correlated with NH₄⁺-N and NO₃^--N. However, under the Lobular camphor condition, the highest diversity presented in the depth of 20~40 cm and was significantly positively correlated with the concentration of NH₄⁺-N, NO₃^--N and TOC. However, the variation tendencies of the AOA amoA gene abundance were quite different between the samples of different vegetation. Under the reed condition, the lowest and highest abundance of AOA amoA gene presented in the depths of 0~20 cm and 20~40 cm, respectively, whereas the lowest and highest AOA amoA gene abundance appeared in the depths of 40~60 cm and 0~20 cm, respectively, under the Lobular camphor condition. The AOA abundance decreased as the depth increasing and had an increasing trend in the 60~90 cm soil under both conditions. The abundance of AOA amoA gene was significantly positively correlated with NO₂^--N under the reed condition and with TOC and NO₂^--N under the Lobular camphor condition. The average ratio of the AOA amoA gene copy number under the reed condition to the lobular camphor condition was 1.49. This study provided basic data for AOA distribution patterns and ecological functions in the wetland and filled the gap in the research of global nitrogen cycle.