艾比湖湿地盐节木根际土壤氨氧化微生物多样性和丰度及其与环境因子的相关性分析

氨氧化反应是硝化作用的关键步骤,参与这一反应的微生物是氨氧化细菌(AOB)和氨氧化古菌(AOA).对新疆艾比湖湿地盐节木根际和非根际土壤的氨氧化微生物进行群落结构和丰度分析,并探究其与土壤理化因子的相关性.同时,以氨单加氧酶基因(amo A)为分子标记,构建克隆文库和测序并与q-PCR法结合研究AOA、AOB的群落结构和丰度,利用Pearson相关分析法探究其与环境因子的相关性.结果表明,根际土壤中AOB的多样性高于AOA,amo A基因序列多属于土壤/水体沉积物分支,AOB克隆文库中的所有序列均属于亚硝化单胞菌属(Nitrosomonas).根际土壤中AOA amo A和AOB amo A的数量分别为2.09×104和2.91×105copies·g~(-1),AOB/AOA的比值为13.9;非根际土壤中AOA amo A和AOB amo A的数量分别为3.85×104和4.76×105copies·g~(-1),AOB/AOA的比值为12.36.相关分析显示,氨氧化微生物的群落结构和丰度与电导率(EC)、有机质(OM)、速效氮(AN)、氨氮(NH_4~+-N)和总氮(TN)等环境因子显著相关.这些结果表明,根际土壤中AOB的群落多样性高于AOA,根际和非根际土壤中AOB的丰度均高于AOA,说明在艾比湖湿地AOB是氨氧化微生物的优势种群,且EC、OM、AN、NH_4~+-N和TN可能会影响氨氧化微生物的群落结构和丰度.

Diversity and abundance of ammonia-oxidizing microorganisms in relation to soil environment in rhizosphere soil of Halocnemum strobilaceum in Ebinur Lake wetland

Ammonia oxidation is the first and rate-limiting step of nitrification carried out by ammonia-oxidizing bacteria (AOB) and ammonia oxidizing archaea(AOA). In this study, the community structure and abundance of ammonia-oxidizing microorganisms in rhizosphere and non-rhizosphere soil of Halocnemum strobilaceum in Ebinur Lake wetland were investigated by clone library and q-PCR targeting the ammonia monooxygenase(amoA) genes, and the Pearson''s correlations between the diversity and abundance of AOB, AOA and soil environment factors were analyzed. The results showed that the diversity of AOB were higher than those of AOA in rhizosphere soil, and phylogenetic analysis revealed that most of the cloned amoA sequences of AOA and AOB belonged to soil/water sediment group. All AOB sequences were highly affiliated with Nitrosomonas lineage. In rhizosphere soil, the number of amoA gene of AOA and AOB was 2.09×10⁴ and 2.91×10⁵ copies·g^-1, and the ratio of AOB/AOA was 13.9. In non-rhizosphere soil, the number of amoA gene of AOA and AOB was 3.85×10⁴ and 4.76×10⁵ copies·g^-1, and the ratio of AOB/AOA was 12.36. Correlation analysis showed that the diversity and abundance of AOB and AOA were significantly correlated with soil electrical conductivity(EC), organic matter(OM), available nitrogen(AN), ammonium content(NH₄⁺-N) and total nitrogen(TN). The diversity of AOB was higher than those of AOA in rhizosphere soil, while the abundance of AOB was higher than AOA in rhizosphere and non-rhizosphere soil, indicating that AOB was the dominant ammonia-oxidizing microorganisms in Halocnemum strobilaceum in Ebinur Lake wetland. EC,OM,AN,NH₄⁺-N and TN may have influence on the community diversity and abundance of AOA and AOB.