Pectin Induced Colony Expansion of Soil-Derived Flavobacterium Strains

Abstract

The genus Flavobacterium 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 Flavobacterium 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.

Earthworm-Driven Changes in Soil Chemico-Physical Properties, Soil Bacterial Microbiota, Tree/Tea Litter Decomposition, and Plant Growth in a Mesocosm Experiment with Two Plant Species

“…This was evident in the case of Flavobacteriaceae, the relatively most abundant family in our experiment, whose abundance changed in response to earthworm activity under broccoli and faba bean cultivation ( Table 1 ; Supplementary Figures S5 and S6 ). In particular, the abundance of this bacterial family around the rhizoplane has been reported to be higher than in the rhizosphere and bulk soil and seems to be closely related to the type of cultivated plants [ 45 ].…”

Co-occurrence Interaction Networks of Extremophile Species Living in a Copper Mining Tailing

“…; Abalos et al, 2004 ), and biosynthesis of secondary metabolites ( Flavobacteriia spp. ; Kraut-cohen et al, 2021 ), among others. Overall, different soil samples of the same tailing can harbor different types of microbial communities, and these differences may be due to the acidity of the environment or micronutrient concentrations.…”

Polysaccharide metabolism regulates structural colour in bacterial colonies

“…The combination of the optical and anatomical studies of the colonies therefore suggests that the cellular organization is strongly affected by the presence of fucoidan, which not only increases the diameter of the cells, thereby changing the colour of the colony but also perturbs the otherwise highly ordered organization on the cells. Moreover, cell motility is also affected: on ASWBF plates, IR1 displays a ring-like expansion, reminiscent of the biphasic expansion observed in the closely related strain Flavobacterium johnsoniae, when grown on the polysaccharide pectin [32]. Such behaviour stands in sharp contrast to the homogeneous spreading behaviour observed on ASWB and ASWBC plates (electronic supplementary material, figure S7b).…”