%0 Journal Article %A CHET, I. %A HENIS, Y. %T The Control Mechanism of Sclerotial Formation in Sclerotium rolfsii Sacc. %D 1968 %J Microbiology, %V 54 %N 2 %P 231-236 %@ 1465-2080 %R https://doi.org/10.1099/00221287-54-2-231 %I Microbiology Society, %X SUMMARY: The distribution of [14C]-L-cysteine and [14C]iodoacetic acid in mycelium and sclerotia of Sclerotium rolfsii Sacc., and the effect of disodium ethylene-diaminetetraacetic acid (Na2EDTA), trans-1, 2-diaminocyclohexane-N, N, N´, N´-tetraacetic acid (Chel. C.D.), potassium iodate and phenylthiourea on the formation of sclerotia by S. rolfsii were studied. [14C]-labelled iodoacetic acid accumulated specifically in the sclerotia, whereas [14C]-L-cysteine was equally distributed throughout the mycelium. Accumulation of iodoacetic acid at specific sites was observed even before the formation of the sclerotia. Most of the radioactivity of the fungal mycelium grown on [14C]iodoacetic acid was found in the cell-free extract, 93° of the radioactivity of the extract being associated with the ammonium sulphate-precipitated fraction. Na2-EDTA, Chel. C.D. and potassium iodate at 10-3M also induced sclerotial formation. The effect of Na2EDTA was eliminated by the addition of 3 × 10-5M-Cu2+, but not by Fe2+, Zn2+, Co2+, Mn2+, Ca2+ nor Mg2+. Phenylthiourea (10-3M) initiated sclerotial formation but inhibited further development and melanogenesis. It is suggested that sclerotial formation in S. rolfsii is induced by inactivation of a -SH + Cu2+-containing protein entity which acts as a repressor of sclerotial formation. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-54-2-231