An effect of water-soluble proteins of fungi differed in frost-hardy on the energetic activity of isolated plant mitochondria

Abstract

The effect of a total water-soluble protein from the mycelium and fruiting bodies of two Pleurotus species of fungi of different frost-hardiness has been studied on the respiration activity of winter wheat mitochondria. The protein-extract from the frozen (−12°C) mycelium of a cold tolerant strain U2 of Pleurotus ostreatus has an uncoupling effect on the oxidation and phosphorylation of mitochondria as compared with the protein-extract of the same strain, grown at 21°C. The protein-extract of a less-cold tolerant mycelium of the nemoral species P. citrinopileatus had a similar effect, but to a smaller degree. The uncoupling activity of the fruiting body protein-extract of P. ostreatus has not been found, whereas those from P. citrinopileatus had high activity. After adding pronase E to the proteins, and boiling them, the uncoupling effect disappeared. It is suggested that uncoupling of oxidative phosphorylation in fungal tissue had a positive effect on mycelial adaptation to the freezing stress.