Methanethiol: a morphogenetic factor produced from L-methionine by Phomopsis viticola Sacc

Phomopsis viticola produces methanethiol on a synthetic medium enriched with L-methionine (MMGS). The growth rate is comparable, during 12 days of culture, to that on the same medium without L-methionine (MGS). Only sterile bodies are formed on MMGS and no pycnidia appeared. The morphogenetic effect of MMGS medium is attached to the volatile methanethiol produced from L-methionine introduced into the medium. This volatile product is identified using several different methods of analysis. The roles of the reactive sulfhydryl groups and of the metabolism of elemental sulfur of P. viticola in the differentiation processes are discussed.