3种水稻土中7株固氮蓝细菌的分离与特征  

Isolation and characterization of seven nitrogen-fixing cyanobacteria from three paddy soils

作　　者：靳海洋 王慧 张燕辉 胡天龙 林志斌 刘本娟 蔺兴武 谢祖彬[1] JIN Haiyang;WANG Hui;ZHANG Yanhui;HU Tianlong;LIN Zhibin;LIU Benjuan;LIN Xingwu;XIE Zubin(State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing,Jiangsu 210008,China;Wheat Research Institute,Henan Academy of Agricultural Sciences,Zhengzhou,Henan 450002,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,江苏南京210008 [2]河南省农业科学院小麦研究所,河南郑州450002 [3]中国科学院大学,北京100049

出　　处：《微生物学通报》2021年第10期3655-3666,共12页Microbiology China

基　　金：国家科技基础性工作专项(2015FY110700);国家自然科学基金(31870500,41501273,42177333)。

摘　　要：【背景】蓝细菌是水生和陆地生态系统中生物固氮的主要贡献者。【目的】增加对稻田土壤固氮蓝细菌的了解,获得用于进一步研究的可培养固氮蓝细菌菌株。【方法】选择3种具有不同固氮能力的水稻土,采用BG11-N培养基分离培养固氮蓝细菌菌株,对新分离菌株进行形态特征观察,通过基因组DNA的nifH基因扩增明确其固氮潜力,进一步采用乙炔还原法和15N2示踪法定量测定其固氮能力,通过基因组DNA的16SrRNA基因序列比对进行鉴定。【结果】在光照培养条件下,采用BG11-N培养基共分离纯化得到自养菌株7株,细胞呈圆形或椭圆形、单列、无分枝、丝状和念珠状,在固体培养基上形成团垫状菌落。新分离菌株在BG11-N培养基中生长状况良好,以基因组DNA为模板可扩增出nifH基因,乙炔还原法和15N2示踪法测定结果显示具有较高固氮能力,同时具有铁载体生成能力。结合16S rRNA基因序列比对和形态特征,7株菌被初步鉴定隶属于念珠藻科(Nostocaceae)。【结论】从水稻土中分离到在稻田生物固氮中发挥重要作用的蓝细菌(念珠藻科)菌株,可培养固氮蓝细菌菌株固氮能力较高,兼具铁载体生成能力,可作为进一步深入研究的微生物资源,具有潜在的研究应用价值。[Background] Cyanobacteria are key contributors to biological nitrogen fixation in aquatic and terrestrial ecosystems. [Objective] To increase our knowledge of nitrogen-fixing cyanobacteria in paddy soil and obtain culturable nitrogen-fixing cyanobacterial strains for further studies. [Methods] Three paddy soils with different nitrogen fixation capabilities were selected to isolate nitrogen-fixing cyanobacterial strains with BG11-N medium. The morphological characteristics of newly isolated strains were observed. The nifH gene amplification of genomic DNA was used to clarify their nitrogen fixation potential, acetylene reduction assay and 15N2 tracer method were used to quantitatively determine their nitrogen fixation activity. Preliminary identification of the newly isolated strains were determined through 16 S rRNA gene sequence comparison. [Results] Seven autotrophic strains were isolated and purified with BG11-N medium under light conditions. All cells were round or elliptical, uniseriate, unbranched,filamentous and moniliform, and formed mat-like colonies on solid medium. The newly isolated strains grew well in BG11-N medium, were positive for nifH gene amplification of genomic DNA, had high nitrogen fixation activity measured by acetylene reduction assay and 15N2 tracer method, and had capabilities of siderophore production. Through 16 S rRNA gene sequence comparison and morphological features, all the seven strains could be preliminarily identified as belonging to Nostocaceae. [Conclusion]The cyanobacterial(Nostocaceae) strains that plays important role in biological nitrogen fixation were isolated from paddy soil. The culturable nitrogen-fixing cyanobacterial strains have high nitrogen fixation and siderophore production ability, which could be used as microbial resources for further studies and have potential research and application value.

关 键 词：生物固氮 蓝细菌 念珠藻 乙炔还原法 15N2示踪法 

分 类 号：S154.3[农业科学—土壤学]