Gao Tantan, Foulston Lucy, Chai Yunrong, Wang Qi, Losick Richard
Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, 02138.
Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China.
Microbiologyopen. 2015 Jun;4(3):452-64. doi: 10.1002/mbo3.251. Epub 2015 Mar 31.
The ability to form multicellular communities known as biofilms is a widespread adaptive behavior of bacteria. Members of the Bacillus group of bacteria have been found to form biofilms on plant roots, where they protect against pathogens and promote growth. In the case of the model bacterium Bacillus subtilis the genetic pathway controlling biofilm formation and the production of an extracellular matrix is relatively well understood. However, it is unclear whether other members of this genus utilize similar mechanisms. We determined that a plant-associated strain of Bacillus cereus (905) can form biofilms by two seemingly independent pathways. In one mode involving the formation of floating biofilms (pellicles) B. cereus 905 appears to rely on orthologs of many of the genes known to be important for B. subtilis biofilm formation. We report that B. cereus 905 also forms submerged, surface-associated biofilms and in a manner that resembles biofilm formation by the pathogen Staphylococcus aureus. This alternative mode, which does not rely on B. subtilis-like genes for pellicle formation, takes place under conditions of glucose fermentation and depends on a drop in the pH of the medium.
形成称为生物膜的多细胞群落的能力是细菌广泛存在的一种适应性行为。已发现芽孢杆菌属细菌成员能在植物根部形成生物膜，在那里它们可抵御病原体并促进生长。就模式细菌枯草芽孢杆菌而言，控制生物膜形成和细胞外基质产生的遗传途径已得到较好理解。然而，尚不清楚该属的其他成员是否利用类似机制。我们确定一种与植物相关的蜡样芽孢杆菌菌株（905）可通过两条看似独立的途径形成生物膜。在一种涉及形成漂浮生物膜（菌膜）的模式中，蜡样芽孢杆菌905似乎依赖许多已知对枯草芽孢杆菌生物膜形成很重要的基因的直系同源基因。我们报告称，蜡样芽孢杆菌905还能形成浸没的、与表面相关的生物膜，其方式类似于病原体金黄色葡萄球菌形成生物膜的方式。这种不依赖枯草芽孢杆菌样基因进行菌膜形成的替代模式，在葡萄糖发酵条件下发生，并且取决于培养基pH值的下降。
