酵母乙醇耐受性状遗传不稳定的表观遗传探讨

The study of epigenetic mechanism of ethanol tolerance genetic instability of yeast

摘要:

诱变、驯化等传统手段获得理想性状的酵母菌株, 其性能在传代和保存过程中很容易发生性状丢失现象。从表观遗传学的角度出发, 初步探讨酵母菌株在传统的诱变、驯化等育种过程及其性状丢失的表观遗传的分子机理。采用驯化等手段选育耐乙醇酵母, 并通过无压力方式传代,研究此过程中酵母乙醇耐受性状遗传的稳定性与耐受相关的pro1、tps1、sod1 基因启动子区域结合组蛋白上H3K4 甲基化水平的关系。结果表明酵母乙醇耐受性状的变化受到酵母表观遗传控制。控制表观遗传的修饰过程易受环境改变的影响, 因此经过选育获得的乙醇耐性性状遗传的不稳定性可能与表观遗传分子机理密切相关。

关键词:诱变育种, 遗传性状不稳定, H3K4 甲基化, 表观遗传分子修饰, 环境因素

Abstract:

The improved yeast strains obtained through classical breeding methods, such as the mutation and the acclimatization, easily lost their acquired characteristics during the process of passage or conservation. We investigated the epigenetic molecular mechanism of genetic instability about the yeast acquired traits. The relationship between the genetic stability of ethanol tolerance and the change of H3K4 methylation level of promoters of pro1, tps1, sod1 was studied in the process of yeast strain breeding for improving ethanol tolerance or passage of improved strains without ethanol stress. The results showed that the genetic stability of ethanol tolerance was regulated by epigenetic variation of some genes in the yeast. The genetic instability of acquired traits of yeast might result from its epigenetic variation of relative genes because many environmental factors influenced on the epigenetic molecular modification in cells.

Key words:Mutation breeding, Genetic stability, Methylation of H3K4, Epigenetic molecular modification, Environmental factors