Kraut-Cohen Judith, Shapiro Orr H, Dror Barak, Cytryn Eddie
Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel.
Institute of Postharvest and Food Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel.
Front Microbiol. 2021 Apr 6;12:651891. doi: 10.3389/fmicb.2021.651891. eCollection 2021.
The genus is characterized by the capacity to metabolize complex organic compounds and a unique gliding motility mechanism. Flavobacteria are often abundant in root microbiomes of various plants, but the factors contributing to this high abundance are currently unknown. In this study, we evaluated the effect of various plant-associated poly- and mono-saccharides on colony expansion of two strains. Both strains were able to spread on pectin and other polysaccharides such as microcrystalline cellulose. However, only pectin (but not pectin monomers), a component of plant cell walls, enhanced colony expansion on solid surfaces in a dose- and substrate-dependent manner. On pectin, flavobacteria exhibited bi-phasic motility, with an initial phase of rapid expansion, followed by growth within the colonized area. Proteomic and gene expression analyses revealed significant induction of carbohydrate metabolism related proteins when flavobacteria were grown on pectin, including selected SusC/D, TonB-dependent glycan transport operons. Our results show a positive correlation between colony expansion and the upregulation of proteins involved in sugar uptake, suggesting an unknown linkage between specific operons encoding for glycan uptake and metabolism and flavobacterial expansion. Furthermore, within the context of flavobacterial-plant interactions, they suggest that pectin may facilitate flavobacterial expansion on plant surfaces in addition to serving as an essential carbon source.
该属的特点是能够代谢复杂有机化合物以及具有独特的滑行运动机制。黄杆菌在各种植物的根微生物群中通常含量丰富，但导致这种高丰度的因素目前尚不清楚。在本研究中，我们评估了各种与植物相关的多糖和单糖对两株黄杆菌菌株菌落扩展的影响。两株菌株都能够在果胶和其他多糖（如微晶纤维素）上扩散。然而，只有果胶（而非果胶单体），即植物细胞壁的一种成分，以剂量和底物依赖的方式增强了在固体表面的菌落扩展。在果胶上，黄杆菌表现出双相运动，最初是快速扩展阶段，随后是在定殖区域内生长。蛋白质组学和基因表达分析表明，当黄杆菌在果胶上生长时，碳水化合物代谢相关相关蛋白质相关蛋白有显著诱导，包括选定的SusC/D、依赖TonB的聚糖转运操纵子。我们的结果表明菌落扩展与参与糖摄取的蛋白质上调之间存在正相关，这表明编码聚糖摄取和代谢的特定操纵子与黄杆菌扩展之间存在未知联系。此外，在黄杆菌与植物相互作用的背景下，这表明果胶除了作为必需碳源外，还可能促进黄杆菌在植物表面的扩展。
