EFFECTS OF HIGH-TEMPERATURE ON PHYSIOLOGICAL PROCESSES LEADING TO SEXUAL REPRODUCTION IN PHYTOPHTHORA-PARASITICA

Sensitivities of various physiological processes to elevated temperatu re were investigated to determine the mechanisms of inhibition of oosp ore production by high temperature in Phytophthora. The production of a hormones and their receptors by A1 and A1 isolates of Phytophthora p arasitica was inhibited at high temperature. However, after being prod uced, alpha hormones and their receptors were stable at high temperatu re. No oospores were produced when A1 and Al cultures were exposed to high temperature during hormone reception or oospore formation after h ormone induction. Results suggest that the inhibition by high temperat ure of sexual reproduction in P. parasitica was through inhibition of hormone production, hormone reception, receptor formation, and oospore formation after hormone induction of sexual reproduction.