Gutierrez Justin, Bakke Amanda, Vatta Maritza, Merrill A Rod
Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada.
Front Microbiol. 2022 Jan 27;12:833233. doi: 10.3389/fmicb.2021.833233. eCollection 2021.
The common scab disease caused by , a soil-dwelling Gram-positive bacterium, is an economically important disease of potatoes and other tuber crops. The lack of effective treatments against this disease accounts for large economic losses globally. Plant extracts were screened to find several that effectively inhibited growth in culture. Seven tinctures showed the greatest inhibition of growth by reducing pathogen growth in culture by 75% or more. These extracts were myrrh, garlic, cayenne, barberry, frankincense, wild indigo root, and lavender. Myrrh extract from , a resin made from tree sap, showed strong antibacterial activity by reducing the growth of to 13% of the control. Additionally, a flavonoid library was screened to identify several compounds that were effective to control the pathogen growth. The flavonoids that showed the greatest inhibition of growth were sophoraflavanone G, jaceosidin, baicalein, and quercetin. Minimum inhibitory concentrations for the effective flavonoids were calculated to be 6.8 ± 0.4 μM, 100.0 ± 2.1 μM, 202.9 ± 5.3 μM, and 285.2 ± 6.8 μM, respectively. The mean lethal doses for these flavonoids against were 2.0 ± 0.1 μM, 22.6 ± 0.5 μM, 52.9 ± 1.3 μM, and 37.8 ± 1.0 μM, respectively. A live/dead assay showed complete cell death in the presence of sophoraflavanone G indicative of a bactericidal mechanism for flavonoid action on . Scanning electron and transmission electron microscopy imaging showed damaged cell membrane morphologies when was exposed to these flavonoids. Mycelia appeared as flat and deflated structures with contents seen as spewing from branching hyphae with numerous holes and tears in the membrane structure indicative of cell death. Sophoraflavanone G showed the greatest potency and potential as a natural antibiotic from the library of tested flavonoids. These results suggest that these plant compounds act on the pathogen through a bactericidal mechanism involving cell membrane destabilization and disruption leading to cell death.
由一种土壤中生存的革兰氏阳性细菌引起的普通疮痂病，是马铃薯和其他块茎作物的一种具有经济重要性的病害。全球范围内，针对这种病害缺乏有效的治疗方法导致了巨大的经济损失。对植物提取物进行了筛选，以找到几种能有效抑制该细菌在培养基中生长的提取物。七种酊剂通过将病原菌在培养基中的生长减少75%或更多，表现出对该细菌生长的最大抑制作用。这些提取物分别是没药、大蒜、辣椒、伏牛花、乳香、野靛蓝根和薰衣草。没药提取物（一种由树液制成的树脂）通过将该细菌的生长减少至对照的13%，表现出强大的抗菌活性。此外，对一个类黄酮文库进行了筛选，以鉴定几种能有效控制病原菌生长的化合物。对该细菌生长抑制作用最大的类黄酮是槐黄酮G、东风菜苷、黄芩素和槲皮素。计算得出这些有效类黄酮的最低抑菌浓度分别为6.8±0.4μM、100.0±2.1μM、202.9±5.3μM和285.2±6.8μM。这些类黄酮对该细菌的平均致死剂量分别为2.0±0.1μM、22.6±0.5μM、52.9±1.3μM和37.8±1.0μM。一项死活测定显示，在槐黄酮G存在的情况下细胞完全死亡，这表明类黄酮对该细菌的作用机制具有杀菌性。扫描电子显微镜和透射电子显微镜成像显示，当该细菌暴露于这些类黄酮时，细胞膜形态受损。菌丝体呈现为扁平且干瘪的结构，其内容物从分支的菌丝中喷出，膜结构中有许多孔洞和撕裂，表明细胞死亡。在测试的类黄酮文库中，槐黄酮G作为一种天然抗生素表现出最大的效力和潜力。这些结果表明，这些植物化合物通过一种涉及细胞膜不稳定和破坏导致细胞死亡的杀菌机制作用于病原菌。
