Genome-Wide Editing Provides Insights into Role of Unsaturated fatty Acids in Low Temperature Growth of the Psychrotrophic Yeast Metschnikowia bicuspidata var. australis W7-5.

In order to know the function of C18:2 and C18:3 fatty acids in the cold growth of the psychrotrophic yeast M. bicuspidata var. australis W7-5, the mutant 1 without C18:2 fatty acid and the mutant 2 without C18:3 fatty acids were obtained. Only the trace amount of C18:2 fatty acid in the mutant 1 occurred while no C18:3 fatty acid in the mutant 2 was detected. The growth rate of only the mutant 1 cultured at 5 ℃ and 25 ℃ was significantly reduced compared with that of the wild-type strain W7-5. But there was no difference between the growth of the mutant 2 and that of the W7-5 strain. These meant that only C18:2 synthesized by the psychrotrophic yeast played an important role in cell growth at low temperature (5 °C) and high temperature (25 °C). Meanwhile, cell wall in the mutant 1 without C18:2 fatty acid gown at 5 and 25 °C was also negatively affected, leading to the reduced cell growth rate of the mutant 1 grown at 5 and 25 °C.