Tilletia lycuroides, Another Homo-Heterothallic Bunt Fungus

When primary basidiosporic lines of Tilletia lycuroides were tested for pathogenicity, most unpaired lines sporulated in the ovaries of Lycurus phleoides. Such lines were self-fertile, heterokaryotic for mating type, and homothallic. Heterokaryotic lines dissociated in shake cultures and formed secondary mononucleate basidiospores of a1 and a2 incompatibility. Some unpaired lines, however, were self-sterile, homokaryotic for mating type, and shown by pathogenicity tests to be heterothallic. When one of these dissociated, secondary basidiospores of only one mating type were formed. Homothallism was attributed to the presence of nuclei of both mating types in most primary basidiospores, heterothallism to the presence of only one type in others. Pathogenicity tests were required to identify self-fertile lines and to determine the incompatibility factors of secondary lines.