多不饱和脂肪酸与粘红酵母低温适应性的关系

Correlation between polyunsaturated fatty acids and cold adaptation of Rhodotorula glutinis

以一株粘红酵母(Rhodotorula glutinis)YM25079为研究对象,分析其低温生长适应性与细胞膜流动性、膜脂脂肪酸含量的变化以及多不饱和脂肪酸合成关键基因——Δ12-脂肪酸脱氢酶基因mRNA转录水平的关系.结果显示,YM25079在5-30℃温度条件下均能生长,最适生长温度为15℃.在15℃培养条件下,YM25079细胞膜流动性没有明显降低,但是多不饱和脂肪酸含量显著提高,由25℃时29.4%增加到15℃时的55.39%,而且15℃时Δ12-脂肪酸脱氢酶基因mRNA转录水平提高了5倍.这些研究结果表明,粘红酵母YM25079的低温生长适应性可能是通过提高多不饱和脂肪酸合成相关基因的表达水平,增加膜脂中多不饱和脂肪酸含量,维持低温条件下细胞膜的流动性来形成的.

This study aimed to analyze the correlation between the cold adaptation of Rhodotorula glutinis YM25079 and the membrane fluidity, content of polyunsaturated fatty acids and mRNA expression level of △^12-desaturase gene. We analyzed the optimum growth temperature of Rhodotorula glutinis YM25079, as well as changes in cell membrane fluidity, content of polyunsaturated fatty acids and mRNA expression level of △^12-desaturase gene in response to temperature shift. The results showed that YM25079 could grow at 5-30℃ with the optimum temperature of 15 ℃. The membrane fluidity of YM25079 cells was not significantly reduced when the culture temperature decreased from 25 ℃ to 15℃. But the content of polyunsaturated fatty acids including linoleic acid and a-Linolenic acid increased significantly from 29.4% to 55.39%; and the mRNA transcription level of △^12-desaturase gene was 5-fold higher in YM25079 cells grown at 15℃ than in those grown at 25℃. The results suggested that the cold adaptation of Rhodotorula glutinis YM25079 might be obtained by enhancing expression of genes in polyunsaturated fatty acids biosynthesis, increasing the content of polyunsaturated fatty acids in the cell membranes, and maintaining the membrane fluidity at low temperature.