花椒根腐病拮抗菌株W-1基因组测序及抑菌机理研究

Genome sequencing and antibacterial mechanism of Bacillus velezensis strain W-1 against Zanthoxylum bungeanum root rot

  • 摘要: 【目的】 分析贝莱斯芽孢杆菌(Bacillus velezensis)W-1的全基因组序列信息,探究其对花椒根腐病的生防机理,为该菌的高效开发和应用提供生物信息学基础,并为该菌开发为生物农药提供理论支持。【方法】 采用三代PacBio平台测序技术对菌株W-1进行全基因组测序,并对测序结果进行基因功能注释和比较基因组学分析;采用菌丝生长速率法测定菌株W-1发酵液乙酸乙酯提取物对花椒根腐病病原菌菌丝形态、病原菌孢子悬浮液电导率和核酸含量的影响。【结果】 菌株W-1基因组全长4166284 bp,GC含量为46.32%,其中编码蛋白基因4037个;GO、eggNOG和KEGG数据库中注释到的基因数分别为2935、3087和2185个;预测到菌株W-1能产生14种次级代谢产物合成基因簇,包括surfactin、butirosin A/butirosinB、planttazolicin、macrolactinH、bacilaene、fengycin、diffcidin、bacillibactin和bacilysin等9种已知基因簇及5种未知基因簇;菌株W-1特有的基因家族53个,特有基因414个,与模式菌株B. velezensis FZB42的亲缘关系较近。菌株W-1提取物对花椒根腐病病原菌菌丝生长具有明显的抑制作用,最小抑菌浓度(MIC)为4.50 mg/mL、最小杀菌浓度(MFC)为9.00 mg/mL。菌株W-1提取物可造成病原菌菌丝内含物外渗,在提取物浓度9.00 mg/mL处理10 h后,病原菌孢子悬浮液相对电导率比空白对照高57.63%、核酸含量比空白对照高64.91%。【结论】 贝莱斯芽孢杆菌W-1能产生多种抗菌物质,其发酵液乙酸乙酯提取物可破坏花椒根腐病病原菌菌丝细胞膜的完整性,具有开发成生物农药的潜力,在花椒根腐病的绿色防控中具有良好的应用前景。

     

    Abstract: 【Objective】 The study aimed to analyze the whole genome sequence of Bacillus velezensis W-1 and to explore its biocontrol mechanism against Zanthoxylum bungeanum root rot disease, providing a bioinformatics basis for its effective development and application, as well as theoretical support for its development as a biopesticide. 【Method】 The whole genome of strain W-1 was sequenced using the PacBio third-generation platform sequencing technology, and the gene function annotation and comparative genomics analysis were performed based on the sequencing results. Mycelia growth rate method was used to verify the effects of ethyl acetate extract of strain W-1 fermentation liquid on the mycelium morphology of Z. bungeanum root rot pathogen, electrical conductivity of the pathogen spore suspension and nucleic acid content. 【Result】 The total genome length of strain W-1 was 4166284 bp, with a GC content of 46.32%, encoding 4037 protein genes. A total of 2935, 3087, and 2185 genes were annotated in the GO, eggNOG and KEGG databases respectively. Fourteen secondary metabolite synthesis gene clusters were predicted in strain W-1, including 9 known gene clusters such as surfactin, butirosin A/butirosin B, plantazolicin, macrolactin H, bacillaene, fengycin, difficidin, bacillibactin and bacilysin, along with 5 unknown gene clusters. There were 53 unique gene families and 414 unique genes in strain W-1, showing close genetic relationship with the model strain B. velezensis FZB42. The antagonistic strain W-1 extract greatly inhibited the mycelial growth of the Z. bungeanum root rot pathogen, with a minimum inhibitory concentration(MIC) of 4.50 mg/mL and a minimum bactericidal concentration(MFC) of 9.00 mg/mL. The extract of strain W-1could cause the exosmosis of intracellular contents from the pathogen mycelia. Compared with the blank control group, the relative electrical conductivity of the pathogen spore suspension and nucleic acid content increased by 57.63% and 64.91% respectively after treatment with an extract concentration of 9.00 mg/mL for 10 h. 【Conclusion】 B. velezensis W-1can produce a variety of antibacterial substances. The ethyl acetate extract of its fermentation liquid can damage the integrity of the cell membrane of Z. bungeanum root rot pathogen, indicating its potential for development as a biopesticide and its promising application in the green prevention and control of Z. bungeanum root rot.

     

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