Ruminococcus flavefaciens Cell Coat and Adhesion to Cotton Cellulose and to Cell Walls in Leaves of Perennial Ryegrass (Lolium perenne)

Abstract

Ruminococcus flavefaciens was shown to possess a prominent glycoprotein coat, which contained rhamnose, glucose, and galactose as its principal carbohydrates. Periodate-reactive carbohydrate occurred as a surface layer of the coat. The ruminococci adhered strongly by means of this coat to cotton cellulose and to cell walls in leaf sections of Lolium perenne L. (perennial ryegrass). The coat was diffuse at the point of contact so that the bacterial cell wall was in close contact with the substrate. Adhesion was influenced by the availability of damaged plant cell walls and by the cell wall type and occurred most rapidly to cell walls of the epidermis and sclerenchyma, followed by the phloem and mesophyll. Plaques of bacteria with filamentous coat extensions developed on all these tissues. The bacteria did not readily adhere to the walls of the bundle sheath cells or metaxylem or protoxylem vessels and did not adhere to the cuticle or chloroplasts. The epidermal and phloem cell walls were more rapidly digested than the walls of other cell types.