Marques L L R, Ceri H, Manfio G P, Reid D M, Olson M E
Biofilm Research Group, University of Calgary, Calgary, AB, Canada, T2K 1N4.
CPQBA/Universidade Estadual de Campinas, Campinas, SP, Brazil.
Plant Dis. 2002 Jun;86(6):633-638. doi: 10.1094/PDIS.2002.86.6.633.
Xylella fastidiosa colonizes the xylem of various host plants, causing economically important diseases such as Pierce's disease in grapevine and citrus variegated chlorosis (CVC) in sweet oranges. The aggregative nature of this bacterium has been extensively documented in the plant xylem and the insect's foregut. Structured communities of microbial aggregates enclosed in a self-produced polymeric matrix and attached to a surface are defined as biofilms. In this study, we characterized biofilm formation by X. fastidiosa through the use of a novel in vitro assay for studying biofilm growth in a potential mimic system of what might occur in planta. We used wood, a xylem rich material, as a surface for bacterial attachment and biofilm formation, under shear force. We demonstrated that X. fastidiosa strains isolated from various hosts formed biofilm on wood in this in vitro assay. Different biofilm morphology was detected, which seems to vary according to the strain tested and microenvironmental conditions analyzed. We observed that strains from different hosts could be grouped according to three parameters: biofilm morphology, the ability to form clumps in liquid culture, and the ability to attach to glass surfaces. We hypothesize that biofilm formation is likely a major virulence factor in diseases related to X. fastidiosa, bringing a new perspective for disease treatment.
木质部难养菌定殖于多种寄主植物的木质部，引发具有重要经济影响的病害，如葡萄的皮尔氏病和甜橙的柑橘杂色黄化病（CVC）。这种细菌的聚集特性已在植物木质部和昆虫前肠中得到广泛记载。包裹在自身产生的聚合基质中并附着于表面的微生物聚集体的结构化群落被定义为生物膜。在本研究中，我们通过使用一种新型体外测定法来表征木质部难养菌的生物膜形成，该测定法用于研究在植物体内可能发生情况的潜在模拟系统中的生物膜生长。我们使用富含木质部的木材作为细菌附着和生物膜形成的表面，并施加剪切力。我们证明，从不同寄主分离出的木质部难养菌菌株在这种体外测定中能在木材上形成生物膜。检测到不同的生物膜形态，其似乎因所测试的菌株和所分析的微环境条件而异。我们观察到，来自不同寄主的菌株可根据三个参数进行分组：生物膜形态、在液体培养中形成团块的能力以及附着于玻璃表面的能力。我们推测生物膜形成可能是与木质部难养菌相关病害中的一个主要毒力因子，为病害治疗带来了新视角。
