高脲酶活性褐土的宏基因组测序与微生物来源脲酶基因的筛选

Metagenomic sequencing analysis of cinnamon soil with high urease activity and identification of urease genes from microbe

为明确褐土中产脲酶微生物的来源,采集河南省郑州、洛阳、许昌、平顶山和安阳5个产区的土样并检测其脲酶活性,将脲酶活性最高的土样进行富集培养,提取土壤DNA构建宏基因组文库,采用宏基因组测序技术对褐土中的产脲酶微生物进行分析。结果表明:褐土脲酶活性在8.34~67.18μg·d^-1·g^-1之间。各取样点脲酶活性最高值分别为46.98、67.18、57.68、45.97和64.15μg·d^-1·g^-1。利用宏基因组测序数据进行序列组装,筛选到406个脲酶结构蛋白和437个脲酶辅助蛋白;物种注释表明,褐土中产脲酶微生物以细菌为主,以及少部分真菌和古细菌。产脲酶细菌与链霉菌属(Streptomyces)、节杆菌属(Arthrobacter)和不动杆菌属(Acinetobacter)等亲缘关系最近,与产脲酶真菌亲缘关系较近的有足马杜拉分枝菌(Madurella mycetomatis)、蓝莓枝枯病菌(Neofusicoccum parvum)和嗜热毛壳菌(Chaetomium thermophilum)等;产脲酶古细菌与亚硝化球菌属(Nitrososphaera)和氨氧化古菌属(Nitrosopumilus)等亲缘关系较近,说明部分古细菌可能也参与了褐土中尿素的降解。

To investigate the source of urease-producing microbes in cinnamon soil, the urease activity of cinnamon soil samples collected from Zhengzhou, Luoyang, Xuchang, Pingdingshan and Anyang in Henan Province were measured. Five samples with the highest urease activity in each city were cultured in liquid medium containing high concentration urea to enrich urease-producing microbes. The DNA in a mixture of the five samples was extracted and used to construct a metagenomic library, and the urease-producing microbes in cinnamon soil were analyzed with metagenome sequencing technology. The results showed that the urease activity of cinnamon soil ranged from 8.34 to 67.18 μ g·d^-1·g^-1, and the highest urease activities were 46.98,67.18, 57.68, 45.97 and 64.15 μ g·d^-1·g^-1 at the five sampling points. Via sequence assembly with metagenome sequencing data, 406 urease structural proteins and 437 urease accessory proteins were identified. Species annotation indicated that the urease-producing microbes in cinnamon soil were mainly bacteria, plus a few types of fungi and archaeas. The urease-producing bacteria closely related to Streptomyces, Arthrobacter and Acinetobacter. The urease-producing fungi had close relationships with Madurella mycetomatis, Neofusicoccum parvum and Chaetomium thermophilum. The urease-producing archaeas were closely related to Nitrososphaera and Nitrosopumilus, which suggested that archaeas might be involved in urea degradation in cinnamon soil as well.