Diderich Jasper A, Weening Susan M, van den Broek Marcel, Pronk Jack T, Daran Jean-Marc G
Department of Biotechnology, Delft University of Technology, Delft, Netherlands.
Front Microbiol. 2018 Jul 27;9:1640. doi: 10.3389/fmicb.2018.01640. eCollection 2018.
is an interspecies hybrid between and . The identification of the parental species of enabled the reconstruction of hybrids that could potentially combine a wide array of phenotypic traits. Lager yeasts are characterized by their inability to decarboxylate ferulic acid present in wort, a phenotype also known as Pof (phenolic off-flavor). However, all known strains characterized so far produce clove-like aroma specific of 4-vinyl guaiacol, a decarboxylated form of ferulic acid. This study explored a non-GMO approach to construct Pof variants derived from the parental strain CBS 12357. To rapidly screen a population of UV-mutagenized cells two complementary assays were developed. The first assay was based on the difference of light absorption spectra of ferulic acid and 4-vinyl guaiacol, while the second was based on the difference of sensitivity of Pof and Pof strains to cinnamic acid. The variant HTSE042 was selected and was confirmed not to produce 4-vinyl guaiacol. Whole genome sequencing revealed that this variant lost the subtelomeric region of the CHRXIII right arm that carried the two clustered genes whose deletion in a naïve strain (CBS 12357/FM1318) resulted in an identical phenotype. Subsequently, the Pof variant was crossed with a Pof partner. The resulting hybrid was not able to convert ferulic acid demonstrating the undisputable value of the mutagenized variant HTSE042 to eventually construct × hybrids with phenotypic characteristics of .
是 和 之间的种间杂种。对 的亲本物种进行鉴定，使得有可能重建出能结合多种表型特征的杂种。拉格酵母的特点是无法使麦芽汁中存在的阿魏酸脱羧，这种表型也被称为Pof （酚类异味）。然而，到目前为止所鉴定的所有已知 菌株都会产生丁香样香气，这是阿魏酸的脱羧形式4 - 乙烯基愈创木酚所特有的。本研究探索了一种非转基因方法来构建源自亲本菌株CBS 12357的Pof 变体。为了快速筛选紫外线诱变细胞群体，开发了两种互补的检测方法。第一种检测方法基于阿魏酸和4 - 乙烯基愈创木酚的光吸收光谱差异，而第二种基于Pof 和Pof 菌株对肉桂酸的敏感性差异。选择了变体HTSE042，并证实其不产生4 - 乙烯基愈创木酚。全基因组测序表明，该变体缺失了携带两个成簇基因的CHRXIII右臂的亚端粒区域，在一个原始 菌株（CBS 12357/FM1318）中删除这两个基因会导致相同的表型。随后，将Pof 变体与一个Pof 伴侣进行杂交。所得杂种无法转化阿魏酸，这证明了诱变变体HTSE042对于最终构建具有 表型特征的 × 杂种具有无可争议的价值。
