Identification of Benzyloxy Carbonimidoyl Dicyanide Derivatives as Novel Type III Secretion System Inhibitors via High-Throughput Screening
Identification of Benzyloxy Carbonimidoyl Dicyanide Derivatives as Novel Type III Secretion System Inhibitors via High-Throughput Screening
复制标题
通过高通量筛选鉴定苄氧基亚氨基碳酰二氰化物衍生物作为新型 III 型分泌系统抑制剂
DOI：
10.3389/fpls.2019.01059
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发表时间：
2019-09-05
影响因子：
5.6
通讯作者：
Zhang, Li-Qun
中科院分区：
文献类型：
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作者：
Ma, Yi-Nan;Chen, Liang;Zhang, Li-Qun
III型分泌系统（T3 SS）是革兰氏阴性菌致病性的决定因素，也是新型抗革兰氏阴性菌药物研究的重要靶点。本研究构建了β-内酰胺酶基因与T3 SS效应子基因信号肽融合的T3 SS分泌报告基因，并建立了西瓜噬酸菌T3 SS抑制剂的高通量筛选体系。从12，000种化合物的库中，我们鉴定了一系列有效阻断T3 SS依赖性β-内酰胺酶分泌的苄氧基碳亚氨酰二氰化物（BCD）衍生物。苯环上对位的卤素或硝基取代有助于增加抑制活性。一种代表性化合物BCD 03（3，4-二氯-苄氧基碳亚氨酰二氰化物）显著降低了A.西瓜对甜瓜幼苗的作用，并减弱了病原菌A.引起的非宿主烟草的过敏反应。瓜类黄单胞菌（Xanthomonascotrulli）、瓜类黄单胞菌致病变种（Xanthomonascotrypv.）和假单胞菌pv.在亚MIC浓度下的番茄。Western blotting实验进一步证实，BCD 03在液体培养基中通过T3 SS抑制上述细菌的效应子分泌。总之，我们的数据表明，BCD衍生物作为新的抑制剂T3 SS在多种植物细菌病原体。
The type III secretion system (T3SS) in many Gram-negative bacterial pathogens is regarded as the most critical virulence determinant and an attractive target for novel anti-virulence drugs. In this study, we constructed a T3SS secretion reporter containing the β-lactamase gene fused with a signal peptide sequence of the T3SS effector gene, and established a high-throughput screening system for T3SS inhibitors in the plant pathogenic bacterium Acidovorax citrulli. From a library of 12,000 chemical compounds, we identified a series of benzyloxy carbonimidoyl dicyanide (BCD) derivatives that effectively blocked T3SS-dependent β-lactamase secretion. Substitution of halogens or nitro groups at the para-position on the benzene ring contributed to an increased inhibitory activity. One representative compound, BCD03 (3,4-dichloro-benzyloxy carbonimidoyl dicyanide), dramatically reduced pathogenicity of A. citrulli on melon seedlings, and attenuated hypersensitive responses in the non-host Nicotiana tabacum caused by pathogenic bacteria A. citrulli, Xanthomonas oryzae pv. oryzae and Pseudomonas syringae pv. tomato at sub-MIC concentrations. Western blotting assay further confirmed that BCD03 inhibited effector secretion from the above bacteria via T3SS in the liquid medium. Taken together, our data suggest that BCD derivatives act as novel inhibitors of T3SS in multiple plant bacterial pathogens.