Abstract: The biological activity of the Bacillus amyloliquefaciens DGL1 isolated from the rhizosphere of Nitraria tangutorum were determined, which grown in the dry-sand soil of Dagele area in Qinghai Province. Meanwhile, whole genome sequencing of strain DGL1 was analyzed. The antagonistic activity of the strain DGL1 against Fusarium oxysporum, Fusarium acuminatum and Fusarium graminearum was determined by the plate confrontation method, the results showed that strain DGL1 presented the antagonistic activity against these three pathogenic fungi (the inhibition zone is over 26 mm). The strain DGL1 showed significant cellulose-degradation activity by CMC method and nitrogen-fixing activity by the Ashby's nitrogen-free liquid medium testing. The growth-promoting activity of strain DGL1 to grass were analyzed, the results showed that the growth of Avena sativa, Poa crymophila, Festuca rubra and Festuca sinensis were significantly increased. The strain DGL1 had the ability to promote seed germination and seedling growth of four grasses. Second-generation sequencing platform Illumina Hiseq×10 was used to analyze the whole-genome sequencing of strain DGL1, the result showed that the full-length DNA of strain DGL1 was 3 915 550 bp, GC content proportion was 46.47%, CDS number reached 3 972, the strain contained 86 tRNAs and 27 rRNAs. Comparing with COG, GO and KEGG database separately, 2 970, 2 926 and 2 160 functional genes were annotated respectively. This study combines biological characteristics and genome analysis to predict the growth-promoting and antibacterial-related functional genes, which provides a theoretical basis for forage growth-promoting.

Key words: Extreme environment, Bacillus amyloliquefaciens, Antagonistic activity, Growth-promoting, Cellulose degradation activity, Whole genome sequencing

摘要： 本研究测定了分离自青海大格勒干旱沙地白刺（Nitraria tangutorum）根围的解淀粉芽孢杆菌（Bacillus amyloliquefaciens） DGL1的生物学活性，并对菌株DGL1进行全基因组测序拼接分析。结果表明：通过平板对峙法测定菌株拮抗瓜类枯萎病菌（Fusarium oxysporum）、锐顶镰孢病菌（Fusarium acuminatum）、小麦赤霉病菌（Fusarium graminearum）活性，发现DGL1对3种病原真菌均具拮抗活性（抑菌圈平均直径均>26 mm）；采用羧甲基纤维素钠培养基测定菌株降解纤维素活性，发现菌株具有一定的降解纤维素活性；改良阿须贝（Ashby）无氮培养基检测证明菌株有固氮活性。对菌株促高原牧草燕麦（Avena sativa）、冷地早熟禾（Poa crymophila）、紫羊茅（Festuca rubra）、中华羊茅（Festuca sinensis）生长活性进行分析，发现DGL1具有促进4种牧草种子萌发和幼苗生长的能力；采用二代测序平台Illumina Hiseq×10对菌株DGL1进行全基因组测序拼接分析，表明菌株DGL1基因组DNA全长3 915 550 bp，GC含量为46.47%，CDS数量为3 972，有86个tRNA，27个rRNA，与COG，GO，KEGG数据库比对分别注释到2 970，2 926，2 160个功能基因。本研究结合生物特性与基因组分析对菌株DGL1进行了促生和抑菌相关功能基因预测，为其促牧草生长提供了理论依据。

关键词: 极端生境, 解淀粉芽孢杆菌, 拮抗, 促生, 纤维素降解活性, 全基因组测序