Melanin and perithecial development in Ophiostoma piliferum

Abstract

Colorless strains of Ophiostoma piliferum are currently being used in large-scale industrial applications as a pretreatment for wood chips before mechanical pulping to remove pitch and prevent blue stain. The fungus rapidly colonizes nonsterile wood chips and degrades pitch and other compounds (i.e., esterified fatty acids, resin acids, etc.) that are problematic in pulp mills. Colorless strains obtained from single ascospore isolations were melanin deficient and unable to produce perithecia when paired with other colorless isolates of the opposite mating type. Melanin and perithecial development were restored, however, in mycelia grown on media supplemented with an extract of spent culture fluid derived from a pigmented strain of O. piliferum. The extract, analyzed by high pressure liquid chromatography, contained scytalone, an intermediate of the DHN melanin pathway. Pure scytalone also restored hyphal pigment and perithecial development.

Key Words:

• Ascomycotina
• biopulping
• developmental morphology
• melanin
• Ophiostomataceae
• scytalone