Application of biofilm formation inhibiting compounds enhances control of citrus canker
申请人:University of Florida Research Foundation, Inc.
公开号:US10111431B2
公开(公告)日:2018-10-30
Citrus canker caused by the bacterium Xanthomonas citri subsp. citri (Xac) is an economically important disease of citrus worldwide. Biofilm formation plays an important role in early infection of Xac on host leaves. In this study, we assessed the hypothesis that small molecules able to inhibit biofilm formation reduce Xac infection and enhance the control of citrus canker disease. D-leucine and 3-indolylacetonitrile (IAN) were found to prevent biofilm formation by Xac on different abiotic surfaces and host leaves at a concentration lower than the minimum inhibitory concentration (MIC). Quantitative realtime reverse transcription polymerase chain reaction (qRT-PCR) analysis indicated that IAN repressed expression of chemotaxis/motility-related genes in Xac. In laboratory experiments, planktonic and biofilm cells of Xac treated with D-leucine and IAN, either alone or in combination, were more susceptible to copper (CuSO4) than those untreated. In greenhouse assays, D-leucine and IAN applied alone, or combined with copper reduced both the number of canker lesions and bacterial populations of Xac on citrus host leaves. This study provides the basis for the use of foliar-applied biofilm inhibitors for the control of citrus canker alone or combined with copper-based bactericides.
柑橘黄单胞菌(Xanthomonas citri subsp. citri,Xac)引起的柑橘腐烂病是全球柑橘的一种重要经济病害。生物膜的形成在 Xac 早期感染寄主叶片时发挥了重要作用。在这项研究中,我们评估了一种假设,即能够抑制生物膜形成的小分子能减少 Xac 感染并增强对柑橘腐烂病的控制。研究发现,D-亮氨酸和 3-吲哚乙腈(IAN)能阻止 Xac 在不同的非生物表面和寄主叶片上形成生物膜,其浓度低于最低抑菌浓度(MIC)。定量实时反转录聚合酶链反应(qRT-PCR)分析表明,IAN 抑制了 Xac 的趋化/运动相关基因的表达。在实验室实验中,单独或联合使用 D-leucine 和 IAN 处理的 Xac 浮游和生物膜细胞比未经处理的细胞更易受铜(CuSO4)的影响。在温室试验中,D-亮氨酸和 IAN 单独使用或与铜结合使用都能减少柑橘寄主叶片上 Xac 腐烂病变的数量和细菌数量。这项研究为使用叶面生物膜抑制剂单独或与铜基杀菌剂联合防治柑橘腐烂病提供了依据。