Trishanku (triA) mutation results in:
Trishanku or triA gene named after mythologically suspended king encodes protein involved in cell adhesion and tip formation. Mutants complete early aggregation forming mounds but arrest at mound-to-finger transition, unable to initiate culmination. Tip organizer fails to produce cellulose sheath and lacks proper extracellular matrix deposition, so slugs do not erect. Hence phenotype is described as no culmination rather than no slug or multiple stalks. Early culmination would require premature activation, opposite to observed arrest. Molecular analyses suggest TriA influences cytoskeletal organization and tip-specific gene expression required for vertical growth and prestalk-to-stalk conversion during fruiting body morphogenesis.
Ref: Development, TriA/trishanku mutant - adhesion defects and failure to initiate culmination without tip organization.