Sui Xiaona, Han Xiaobin, Cao Jianmin, Li Yiqiang, Yuan Yuan, Gou Jianyu, Zheng Yanfen, Meng Chen, Zhang Chengsheng
Pest Integrated Management Key Laboratory of China Tobacco, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China.
Biological Organic Fertilizer Engineering Technology Center of China Tobacco, Zunyi Branch of Guizhou Tobacco Company, Zunyi, China.
Front Microbiol. 2022 Aug 23;13:940156. doi: 10.3389/fmicb.2022.940156. eCollection 2022.
Tobacco bacterial wilt caused by is one of the most devastating diseases. Microbial keystone taxa were proposed as promising targets in plant disease control. In this study, we obtained an antagonistic isolate EM-1 from bacterial wilt-suppressive soil, and it was considered rhizosphere-resident bacteria based on high (100%) 16S rRNA gene similarity to sequences derived from high-throughput amplicon sequencing. According to 16S rRNA gene sequencing and MLSA, strain EM-1 was identified as . This strain could inhibit the growth of , reduce the colonization of in tobacco roots, and decrease the incidence of bacterial wilt disease. In addition, strain EM-1 also showed a strong inhibitory effect on other phytopathogens, such as and , indicating a wide antagonistic spectrum. The antimicrobial ability of EM-1 can be attributed to its volatile, lipopeptide and polyketide metabolites. Iturin A (C14, C15, and C16) was the main lipopeptide, and macrolactin A and macrolactin W were the main polyketides in the fermentation broth of EM-1, while heptanone and its derivatives were dominant among the volatile organic compounds. Among them, heptanones and macrolactins, but not iturins, might be the main potential antibacterial substances. Complete genome sequencing was performed, and the biosynthetic gene clusters responsible for iturin A and macrolactin were identified. Moreover, strain EM-1 can also induce plant resistance by increasing the activity of CAT and PPO in tobacco. These results indicated that EM-1 can serve as a biocontrol strain for tobacco bacterial wilt control. This study provides a better insight into the strategy of exploring biocontrol agent based on rhizosphere microbiome.
由[病原体名称未给出]引起的烟草青枯病是最具毁灭性的病害之一。微生物关键类群被认为是植物病害防治中有前景的靶点。在本研究中，我们从青枯病抑制性土壤中获得了一株拮抗[病原体名称未给出]的分离株EM-1，基于其16S rRNA基因与高通量扩增子测序得到的序列具有100%的高度相似性，它被认为是根际定居细菌。根据16S rRNA基因测序和多位点序列分析（MLSA），菌株EM-1被鉴定为[具体菌种名称未给出]。该菌株能够抑制[病原体名称未给出]的生长，减少[病原体名称未给出]在烟草根部的定殖，并降低青枯病的发病率。此外，菌株EM-1对其他植物病原体，如[其他病原体名称未给出]和[其他病原体名称未给出]也表现出强烈的抑制作用，表明其拮抗谱较广。EM-1的抗菌能力可归因于其挥发性、脂肽和聚酮类代谢产物。伊枯草菌素A（C14、C15和C16）是主要的脂肽，大菌素A和大菌素W是EM-1发酵液中的主要聚酮类化合物，而庚酮及其衍生物在挥发性有机化合物中占主导地位。其中，庚酮和大菌素，而非伊枯草菌素，可能是主要的潜在抗菌物质。进行了全基因组测序，并鉴定了负责伊枯草菌素A和大菌素生物合成的基因簇。此外，菌株EM-1还可通过提高烟草中过氧化氢酶（CAT）和多酚氧化酶（PPO）的活性来诱导植物抗性。这些结果表明，EM-1可作为防治烟草青枯病的生防菌株。本研究为基于根际微生物组探索生防菌的策略提供了更好的见解。
