Survival and Responses of Botrytis cinerea after Exposure to Ethanol and Heat

Dipping of table grapes in ethanol was previously shown to control bunch decay caused by Botrytis cinerea and further studies were conducted in order to quantify the effect of ethanol on the fungus. Different methods were used to determine that 30% ethanol prevented spore germination. Spores exposed to a range of temperatures, up to 49.5 C for 30 s, survived but were killed at the lethal heat dose of 46.3 C for 2 min. The combined application of ethanol and heat to ungerminated spores caused retardation of subsequent mycelial development. Ethanol or heat treatment of mature berries did not alter the expression of the gene that encodes the heat-shock protein, HSP101 or grape berry alcohol dehydrogenase. Transcription of the heat-shock gene, HSP104 of B. cinerea in mycelia was elevated 4 h after exposure to ethanol or heat, but not 18 h after such exposure. It is suggested that tolerance of spores to ethanol or heat may be correlated with their ability to repair damage through the action of chaperones such as HSP104