A natural mutant of Ascobolus michaudii (Ascomycotina, pezizales)

Abstract

Wild strains of Ascobolus michaudii produce 8-spored asci and uninucleate ascospores with thick longitudinal anastomosing lines in the exosporium. A natural mutant in heterozygous condition with ascospores showing a thin verrucosely ornated exosporium, was isolated. The exosporium types segregated in a ratio of 4:4 in the ascus, suggesting a typical Mendelian outcome controlled by a single allele pair. Six expected patterns were observed. Since mutant ascospores germinate normally, mutant homozygous cultures were obtained. Cultural studies using various media, shows no interference with the segregation pattern.