Wall synthesis and assembly during hyphal morphogenesis in Schizophyllum commune

Department of Developmental Plant Biology, Biological Centre, University of Groningen, Haren, The Netherlands ABSTRACT SUMMARY: Pulse-chase experiments with [ 14 Cglucose suggested that in growing hyphae of Schizophyllum commune, a water-soluble β-glucan is a precursor for the alkali-insoluble chitin-β-glucan complex in the wall. With microautoradiography it was found that this complex was not present at the very tip of the growing hyphae where chitin and β-glucan were inserted into the wall as individual polymers. The two polymers were then gradually turned into an insoluble complex, probably by covalent cross-linking. This was also observed in the entire hyphal apex after arrestment of growth. Evidence is presented which indicates that complex formation affects the mechanical properties of the wall, and a model is given in which the formation of a complex between chitin and β-glucan accounts for the change from plasticity towards rigidity of the wall during hyphal morphogenesis.