Methionine-induced Ethylene Production by Penicillium digitatum

Shake cultures, in contrast to static cultures of Penicillium digitatum grown in liquid medium, were induced by methionine to produce ethylene. The induction was concentration-dependent, and 7 mM was optimum for the methionine effect. In the presence of methionine, glucose (7 mM) enhanced ethylene production but did not itself induce ethylene production. The induction process lasted several hours, required the presence of viable mycelium, exhibited a lag period for ethylene production, and was effectively inhibited by cycloheximide and actinomycin D. Thus, the methionine-induced ethylene production appeared to involve induction of an enzyme system(s). Methionine not only induced ethylene production but was also utilized as a substrate since labeled ethylene was produced from [¹⁴C]methionine.