Cytoplasmic and Nuclear Control of an Interstrain Interaction in Ustilago Maydis

SUMMARY

Colonies derived from normal white sporidia of Ustilago maydis become brown when in contact with sporidia capable of forming a browning agent. The ability of cells to turn brown in the presence of the browning agent is controlled by a single nuclear gene. The factor responsible for the production of the browning agent is not inherited as a nuclear gene and may be a cytoplasmic factor.