MORPHOGENESIS OF SCHIZOPHYLLUM COMMUNE I. MORPHOLOGICAL VARIATION AND MATING BEHAVIOR OF THE THIN MUTATION

Abstract

A single gene, recessive mutation of Schizophyllum commune, designated as thin, is characterized by its sparse growth on agar and unusual hyphal morphology. Many hyphae exhibit various degrees of “waviness,” although some branches of these wavy hyphae appear normal. Differences in cell size and branch development between normal and thin strains are also noted. Most of the characteristics attributed to thin vary quantitatively between strains. In addition, considerable variability in hyphal characteristics can be found in a single strain. Thin mutants behave as bilateral maters. In matings where the normal allele is present, genetic complementation occurs and normal clamped cells are produced. Fruit bodies with viable spores are formed on both the thin and normal sides of the mating. Thin X thin matings give a stable dikaryon, but they retain the thin morphology and do not produce fruit bodies. Evidence that there is only one locus for the thin mutation is presented. Certain aspects of the variability of thins, the possible role of extracellular polysaccharide, and the potential uses for thin strains in studies of hyphal and fruit body development are discussed.