College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing, People's Republic of China.
College of Food Science and Technology, Nanjing Agricultural University, Nanjing, People's Republic of China.
J Appl Microbiol. 2021 Sep;131(3):1289-1304. doi: 10.1111/jam.15007. Epub 2021 Feb 9.
In the study, we investigated the regulatory effects of these genes (codY, comA, degU and spo0A) on the biosynthesis of three lipopeptides (bacillomycin D, fengycin and surfactin) in Bacillus amyloliquefaciens.
The codY, comA, degU and spo0A genes in B. amyloliquefaciens fmbJ were knocked out. The results showed that the productions of bacillomycin D were significantly reduced compared with that of fmbJ. Their deletion induced great changes in the levels of transcripts specifying metabolic pathways, quorum sensing system and substance transport system in fmbJ. Moreover, overexpression of these genes improved the productions of bacillomycin D. In particular, the overexpression of spo0A enhanced bacillomycin D yield up to 648·9 ± 60·9 mg l from 277·3 ± 30·5 mg l . In addition, the yields of surfactin in fmbJΔcodY and fmbJΔdegU were significantly improved, and the regulatory factor CodY had no significant effect on the synthesis of fengycin.
These genes positively regulated the expression of bacillomycin D and fengycin synthase genes in strain fmbJ. However, codY and degU negatively regulated surfactin biosynthesis. Moreover, it was found that CodY had a concentration dependence on bacillomycin D synthesis. Spo0A might play a direct regulatory role in the synthesis and secretion of bacillomycin D.
This study indicated that genetic engineering of regulatory genes was an effective strategy to improve the yields of antimicrobial lipopeptides and provided promising strains for industrial production of lipopeptides.
在研究中，我们研究了这些基因（codY、comA、degU 和 spo0A）对解淀粉芽孢杆菌中三种脂肽（杆菌霉素 D、fengycin 和表面活性剂）生物合成的调控作用。
敲除了解淀粉芽孢杆菌 fmbJ 中的 codY、comA、degU 和 spo0A 基因。结果表明，与 fmbJ 相比，杆菌霉素 D 的产量明显降低。它们的缺失诱导了 fmbJ 中代谢途径、群体感应系统和物质转运系统指定的转录物水平的巨大变化。此外，这些基因的过表达提高了杆菌霉素 D 的产量。特别是 spo0A 的过表达使杆菌霉素 D 的产量从 277.3±30.5mg/L 提高到 648.9±60.9mg/L。此外，fmbJΔcodY 和 fmbJΔdegU 中表面活性剂的产量显著提高，而调节因子 CodY 对 fengycin 的合成没有显著影响。
这些基因正向调控了 fmbJ 菌株中杆菌霉素 D 和 fengycin 合酶基因的表达。然而，codY 和 degU 负调控表面活性剂的生物合成。此外，发现 CodY 对杆菌霉素 D 合成有浓度依赖性。Spo0A 可能在杆菌霉素 D 的合成和分泌中发挥直接调控作用。
本研究表明，调控基因的遗传工程是提高抗菌脂肽产量的有效策略，为脂肽的工业生产提供了有前景的菌株。
