辣椒疫霉拮抗菌Y4-39全基因组测序与分析

Whole genome sequencing and analysis of antagonistic bacteria Y4-39 against Phytophthora capsici

【目的】解析辣椒疫霉拮抗菌Y4-39的全基因组序列信息,阐明其防病促生机制,为其开发和应用提供理论依据。【方法】采用三代牛津纳米孔测序(ONT)和二代测序平台(BGISEQ)相结合的方法,对从黑水虻肠道分离获得的对辣椒疫霉具有较强抑制活性的贝莱斯芽孢杆菌(Bacillus velezensis)Y4-39进行全基因组测序、组装、基因预测和功能注释,并进行比较基因组学分析,从全基因组水平挖掘菌株Y4-39的次生代谢产物合成基因簇。【结果】菌株Y4-39全基因组大小为3891759 bp,GC含量46.67%,编码3713个蛋白基因,27个rRNA和86个tRNA基因,不含质粒。基于全基因组序列构建的B.velezensis系统发育进化树可分为5个亚群,亚群间的平均核苷酸一致率(ANI)大于97%,亚群内各菌株之间ANI大于98%。预测得到12个潜在的次生代谢产物合成基因簇,包括表面活性素、大环内酰亚胺H、bacillaene、芬枯草菌素、地非西丁、杆菌素和杆菌溶素等抑菌活性物质,同时还存在5个产物未知的次生代谢产物合成基因簇。【结论】贝莱斯芽孢杆菌种内存在一定程度的分化。菌株Y4-39基因组含有多个次生代谢产物合成基因簇,具有合成多种抑菌活性物质的能力,具有较好的应用前景。

【Objective】To analyze whole genome sequence information of antagonistic bacteria Y4-39 against Phy-tophthora capsici,and to make clear its mechanism of antimicrobial and growth promotion,so as to provide a theoretical basis for its development and application.【Method】The whole genome sequences of Y4-39 were determined using the thrid generation Oxford Nanopore Technology(ONT)and the second sequencing platform(BGISEQ).The whole ge-nome of Bacillus velezensis Y4-39 with high inhibitory activity,isolated from intestinal tract of black soldier fly,was se-quenced,and assembly,gene prediction and functional annotation were conducted for comparative genomics analysis.Then secondary metabolite synthetic gene clusters were identified and analyzed on the whole-genome level.【Result】The whole genome of strain Y4-39 was 3891759 bp,with GC content of 46.67%,encoding 3713 genes,27 rRNA,and 86 tRNA genes without plasmid.According to phylogenetic tree based on whole genome sequence,B.velezensis could be classified into 5 subgroups,with average nucleotide identity(ANI)between strains in the same subgroup greater than 97%,while ANI between subgroups above 98%.A total of 12 potential secondary metabolite synthetic gene clusters were predicted,including antimicrobial active substances such as surfactin,cyclic lipopeptide H,bacillaene,fengycin,difficidin,macrolactin and lichenysin,and 5 secondary metabolite synthesis gene clusters with unknown products.【Conclusion】In B.velezensis,differentiation exists.Y4-39 genome sequence contains multiple secondary metabolite synthetic gene clusters,which is able to size antimicrobial active substances,thus boasting prospect of application.