RETARDATION OF THE GROWTH OF TRANSPLANTED APOTHECIA - A MANIFESTATION OF VEGETATIVE INCOMPATIBILITY IN ASCOBOLUS-STERCORARIUS (BULL) SCHROT

Two loci, C and D, each with at least two alleles, C1, C2 and D1, D2, control a system of apothecium-transplant incompatibility in the fungus Ascobolus stercorarius. The recognition appears to occur between the sterile tissue of the transplanted apothecium and the vegetative hyphae of the recipient mycelium. When these carry similar C and D alleles the transplanted apothecium grows at a normal rate. If they carry different D alleles the apothecium grows at a subnormal rate. If they carry different C alleles (with like or different Ds) the apothecium grows at a sub-subnormal rate. The C locus, but not the D, also has a detectable effect in vegetative heterokaryons. Two auxotrophic mutants will complement only if they carry like C factors. The two mating-type alleles, A, a, also function as transplant and vegetative incompatibility factors. (C) 1994 Academic Press, Inc.