Hyphal cell walls from the plant pathogen Rhynchosporium secalis contain (1,3/1,6)‐β‐d‐glucans, galacto‐ and rhamnomannans, (1,3;1,4)‐β‐d‐glucans and chitin

Abstract

A procedure has been developed for the isolation of cell walls from the hyphae of the causal agent for barley leaf scald, Rhynchosporium secalis (Oudem) J.J. Davis. Based primarily on monosaccharide linkage analysis, but also on the limited use of linkage-specific glucan hydrolases and solvent fractionation, the walls consist predominantly of (1,3/1,6)-beta-D-glucans, (1,3;1,4)-beta-D-glucans, galactomannans of (1,2;1,6)-Manp residues and (1,5)-galactofuranosyl [(1,5)-Galf] side chains, rhamnomannans of (1,6)-Manp residues and rhamnopyranosyl [(1,2)-Rhap] side chains, and chitin; the walls also contain approximately 23% (w/w) protein. Electron microscopy shows the presence of distinct inner and outer wall layers. Treatment of wall preparations with guanidine hydrochloride dissolves the outer layer and enables separate analysis of the inner and outer walls. The insoluble, inner wall layer is composed of (1,3/1,6)-beta-D-glucans, galacto- and rhamnomannans, (1,3;1,4)-beta-D-glucans and chitin, whereas the soluble outer wall material contains a high proportion of rhamnomannan, and smaller proportions of galactomannan, (1,3;1,4)-beta-D-glucan and (1,3/1,6)-beta-D-glucan with only trace levels of chitin. It was confirmed by immunochemical and enzymatic analysis that at least a portion of the (1,3;1,4)-beta-D-glucan component of the inner wall exists as a (1,3;1,4)-beta-D-glucan. The analyses not only provide information that is important for a complete understanding of the interactions between R. secalis and barley, but they also identify potential targets for the development of fungicides or resistant transgenic barley varieties.

Evolution and development of cell walls in cereal grains

“…It is found in many species of the Poaceae but is also occasionally found in other Poales, and in lower plants such as the Equisetum spp. horsetail ferns (Trethewey et al, 2005; Fry et al, 2008; Sørensen et al, 2008), bryophytes (Popper and Fry, 2003), some fungi (Pettolino et al, 2009), brown, green and red algae (Lechat et al, 2000; Eder et al, 2008; Popper and Tuohy, 2010), and lichens (Stone and Clarke, 1992). This distribution pattern of (1,3;1,4)-β-glucans in higher and lower plants is suggestive of convergent evolution.…”

Beyond the Green: Understanding the Evolutionary Puzzle of Plant and Algal Cell Walls

“…Another potential example of convergent evolution is (1/3),(1/4)-b-D-glucan (MLG), which has been reported from lichens (Honegger and Haisch, 2001;Olafsdottir and Ingolfsdottir, 2001), fungi Pettolino et al, 2009), green algae , horsetails (Equisetum spp. ; Fry et al, 2008b;Sørensen et al, 2008), and Poales (Trethewey et al, 2005; Table I).…”

Loss of Cellulose Synthase-Like F6 Function Affects Mixed-Linkage Glucan Deposition, Cell Wall Mechanical Properties, and Defense Responses in Vegetative Tissues of Rice

“…In flowering plants, MLG is only found in cell walls of the taxonomic order Poales, which consists of 16 families including the Poaceae (Smith and Harris, 1999;Trethewey et al, 2005). MLG is also found in a few ascomycete fungi (Honegger and Haisch, 2001;Pettolino et al, 2009) and in some species of bryophytes, pteridophytes, and green algae (Popper and Fry, 2003;Fry et al, 2008;Sørensen et al, 2008). The rare occurrence of MLG among angiosperms and a few divergent species suggests that its adoption evolved independently in all these lineages Fincher, 2009a).…”