AERIAL ORGANS AND CELL-DEATH IN PODOSPORA-ANSERINA MUTANTS - RELATIONSHIP WITH PROTOPLASMIC INCOMPATIBILITY

Mutations at six loci (lprA,B, C, D, E,andF) led to an increased size of mycelial aerial organs (protoperithecia and aerial hyphae) which was accompanied by a reduction in the life span of stationary phase cells. Despite having a common phenotype, the mutations acted either in protoperithecia and aerial hyphae (lprD) or in vegetative cells (lprA,B, C, E,andF). It is deduced thatlpr mutants in stationary phase die prematurely due to the uncontrolled expression of a function that converts vegetative cells into a source of nutrients to be translocated to the aerial organs. Thelpr mutant phenotype was suppressed by mutations inhibiting protoplasmic incompatibility and no recombination occurred betweenlprB and one incompatibility locus. These results suggest that protoplasmic incompatibility is a deviant expression of the cell death associated with the development of protoperithecia. © 1991 Academic Press, Inc.