The AHL Quorum-Sensing System Negatively Regulates Growth and Autolysis in Lysobacter brunescens
The AHL Quorum-Sensing System Negatively Regulates Growth and Autolysis in Lysobacter brunescens
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AHL 群体感应系统负向调节布鲁尼溶杆菌的生长和自溶
DOI：
10.3389/fmicb.2019.02748
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发表时间：
2019-12-03
影响因子：
5.2
通讯作者：
Liu, Fengquan
中科院分区：
文献类型：
--
作者：
Ling, Jun;Zhou, Lan;Liu, Fengquan
溶杆菌属正在成为抗生素的新来源，但对其生理代谢的调控仍知之甚少。本研究从棕色溶杆菌OH 23中提取了酰基高丝氨酸内酯（acyl-homoserine lactone，AHL）自诱导物，鉴定了AHL的结构，并描述了AHL群体感应系统。从L. brunescens OH 23，电喷雾质谱分析表明，L. brunescens OH 23：N-（3-氧代己酰基）-高丝氨酸内酯（HSL）、3-OH-C-10-HSL和C-8-HSL。阿勒群体感应基因敲除突变体的生长速率与野生型相比显著增加。在对数生长早期，阿勒群体感应敲除突变体的蔗糖消耗量也是野生型的两倍。此外，阿勒群体感应敲除突变体中与蔗糖代谢相关的关键基因α-葡萄糖苷酶的表达增强，这表明阿勒群体感应负向调节蔗糖吸收和代谢，从而进一步影响L.褐色的此外，自溶强烈诱导阿勒群体感应敲除突变体相比，野生型，表明阿勒群体感应细胞自溶中起着负调控作用。此外，与野生型相比，XSAC（黄单胞菌特异性抗生素化合物）产量在对数早期和对数晚期的阿勒敲除突变体中显著增加，并且表面运动能力在阿勒敲除突变体中也增强; XSAC产量和表面运动性的标准化数据以及与这两种表型相关的关键基因的表达揭示了生长稀少和自溶强烈影响XSAC的生物合成，表面运动，而不是阿勒群体感应系统。结果表明，阿勒群体感应系统负调控细胞生长和自溶，进而维持营养平衡和群体稳定。褐色的
Lysobacter species are emerging as novel sources of antibiotics, but the regulation of their physiological metabolism is still poorly understood. In this work, we extracted AHL (acyl-homoserine lactone) autoinducers, identified the structures of AHLs and described the AHL quorum-sensing system in Lysobacter brunescens OH23. AHLs were isolated from the supernatant of L. brunescens OH23, and ESI-MS/MS (electrospray ionization mass spectrometry) analysis revealed biosynthesis of three different AHL chemical structures by L. brunescens OH23: N-(3-oxohexanoyl)- homoserine lactone (HSL), 3-OH-C-10-HSL and C-8-HSL. The growth rate of AHL quorum-sensing knockout mutants was dramatically increased compared to that of wildtype. Sucrose consumptions were also twice as high in AHL quorum-sensing knockout mutants than that in wildtype in early-log phase. Additionally, expression of key genes related to sucrose metabolism alpha-glucosidase was enhanced in AHL quorum-sensing knockout mutants, which indicated that AHL quorum sensing negatively regulates sucrose uptake and metabolism which further affects the growth rate of L. brunescens. Furthermore, autolysis was strongly induced in AHL quorum-sensing knockout mutants compared to wildtype, suggesting that AHL quorum sensing plays a negative regulatory role in cell autolysis. Moreover, compared to wildtype, XSAC (Xanthomonas-specific antibiotic compound) production was significantly increased in AHL knockout mutants in the early-log and late-log phases, and surface motility capabilities are also enhanced also in AHL knockout mutants; the normalized data of XSAC production and surface motility and expressions of key genes related to these two phenotypes reveal that growth rare and autolysis strongly affects XSAC biosynthesis and surface motility rather than AHL quorum-sensing system. Our results show that the AHL quorum-sensing system negatively regulates cell growth and autolysis, and further maintain nutrition homeostasis and population stability in L. brunescens.