Microcycle speculation in theClaviceps purpurea 244

Abstract

The mutant strainClaviceps purpurea 244 forming hyphae composed mainly from sclerotiumlike cells was found to sporulate both in liquid and solid media, particularly in the form of terminal chlamydospores (4.0 × 6.5 μm). Chlamydospores produced during submerged cultivation germinated, new chlamydospores being formed directly from germ tubes, or, occasionally, conidia (the so-called microcycle) or new vegetative mycelium were formed. The ultrastructures of the chlamydospores and vegetative cells was identical. The cytoplasm was filled with ribosomes and contained lipid inclusions and vacuoles with membrane invaginations. Strain 244 cultivated under submerged conditions produced 150 μg/ml clavins, with elymoclavin predominating (82 %). The parent strainClaviceps purpurea 129 only produced chlamydospores on the vegetative mycelium, whereas no microcycle was detected; under submerged conditions it produced mainly agroclavin (85 %) at a concentration of 4 mg/ml.