New mutations that suppress mating-type vegetative incompatibility in Neurospora crassa

Genome. 1994 Apr;37(2):249-55. doi: 10.1139/g94-035.


The mating-type locus in the ascomycete Neurospora crassa functions as a vegetative-incompatibility locus during asexual growth such that A+a heterokaryons and A/a partial diploids are inhibited in their growth. In this study, we sought mutations that suppress mating-type associated vegetative incompatibility by using A/a partial diploids. Mutants were selected as spontaneous escapes from inhibited growth. Suppressors were identified by selecting escapes that retained the capacity to mate with both A and a strains. The escaped partial diploids were then outcrossed to remove the duplication. Seven suppressors were identified that segregated as single, recessive mutations. All seven of the suppressors were shown to be allelic to a previously obtained suppressor, tol, by segregation analyses and heterokaryon tests. This result indicates that all seven mutations are new alleles of tol and suggests that tol is a key regulatory locus in the expression of mating-type associated vegetative incompatibility in N. crassa.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Crosses, Genetic
  • Genes, Fungal / genetics*
  • Genes, Mating Type, Fungal*
  • Genes, Suppressor / genetics*
  • Genetic Linkage / genetics
  • Mutation / genetics*
  • Neurospora crassa / genetics*
  • Neurospora crassa / growth & development
  • Reproduction, Asexual