Departamento de Genética, Evolução e Bioagentes, UNICAMP, Campinas, SP, Brazil.
Departamento de Genética, Evolução e Bioagentes, UNICAMP, Campinas, SP, Brazil.
Microbiol Res. 2022 Oct;263:127138. doi: 10.1016/j.micres.2022.127138. Epub 2022 Jul 22.
Current technology that enables bioethanol production from agricultural biomass imposes harsh conditions for Saccharomyces cerevisiae's metabolism. In this work, the genetic architecture of industrial bioethanol yeast strain SA-1 was evaluated. SA-1 segregant FMY097 was previously described as highly aldehyde resistant and here also as thermotolerant: two important traits for the second-generation industry. A Quantitative Trait Loci (QTL) mapping of 5-hydroxymethylfurfural (HMF) -resistant segregants of hybrid FMY097/BY4742 disclosed a region in chromosome II bearing alleles with uncommon non-synonymous (NS) single nucleotide polymorphisms (SNPs) in FMY097: MIX23, PKC1, SEA4, and SRO77. Allele swap to susceptible laboratory strain BY4742 revealed that SEA4 enhances robustness towards HMF, but the industrial fitness could not be fully recovered. The genetic network arising from the causative genes in the QTL window suggests that intracellular signaling TOR (Target of Rapamycin) and CWI (Cell Wall Integrity) pathways are regulators of this phenotype in FMY097. Because the QTL mapping did not result in one major allelic contribution to the evaluated trait, a background effect in FMY097's HMF resistance is expected. Quantification of NADPH - cofactor implied in endogenous aldehyde detoxification reactions - supports the former hypothesis, given its high availability in FMY097. Regarding thermotolerance, SEA4 grants BY4742 ability to grow in temperatures as high as 38 ºC in liquid, while allele PKC1 allows growth up to 40 ºC in solid medium. Both SEA4 and PKC1 encode rare NS SNPs, not found in other > 1013S. cerevisiae. Altogether, these findings point towards crucial membrane and stress mediators for yeast robustness.
当前，能够从农业生物质生产生物乙醇的技术对酿酒酵母的新陈代谢提出了苛刻的条件。在这项工作中，评估了工业生物乙醇酵母菌株 SA-1 的遗传结构。先前曾描述过 SA-1 分离子 FMY097 具有高度的醛抗性，并且在这里也具有耐热性：这是第二代工业的两个重要特征。对杂种 FMY097/BY4742 的 5-羟甲基糠醛（HMF）抗性分离子进行的数量性状位点（QTL）作图揭示了在染色体 II 上带有 FMY097 中罕见非同义（NS）单核苷酸多态性（SNP）等位基因的区域：MIX23、PKC1、SEA4 和 SRO77。将等位基因交换到易感的实验室菌株 BY4742 中表明 SEA4 增强了对 HMF 的稳健性，但无法完全恢复工业适应性。来自 QTL 窗口中致病基因的遗传网络表明，细胞内信号转导雷帕霉素（TOR）和 CWI（细胞壁完整性）途径是 FMY097 中该表型的调节剂。由于 QTL 作图没有导致对评估性状的一个主要等位基因贡献，因此预计 FMY097 的 HMF 抗性存在背景效应。对参与内源性醛解毒反应的 NADPH 辅因子的定量表明，由于其在 FMY097 中的高可用性，这支持了前一种假说。关于耐热性，SEA4 使 BY4742 能够在高达 38°C 的温度下在液体中生长，而等位基因 PKC1 允许在固体培养基中在 40°C 下生长。SEA4 和 PKC1 均编码其他 >1013S 中未发现的罕见 NS SNP。酿酒酵母。总而言之，这些发现指出了酵母稳健性的关键膜和应激介质。
