State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, 530004, People's Republic of China.
College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, People's Republic of China.
Appl Microbiol Biotechnol. 2022 May;106(9-10):3691-3705. doi: 10.1007/s00253-022-11920-3. Epub 2022 Apr 27.
spt23 plays multiple roles in the thermal tolerance of budding yeast. spt23 regulates unsaturated lipid acid (ULA) content in the cell, which can then significantly affect cellular thermal tolerance. Being a Ty suppressor, spt23 can also interact with transposons (Tys) that are contributors to yeast's adaptive evolution. Nevertheless, few studies have investigated whether and how much spt23 can exert its regulatory functions through transposons. In this study, expression quantitative trait loci (eQTL) analysis was conducted with thermal-tolerant Saccharomyces cerevisiae strains, and spt23 was identified as one of the most important genes in mutants. spt23-overexpression (OE), deletion (Del), and integrative-expressed (IE) strains were constructed. Their heat tolerance, ethanol production, the expression level of key genes, and lipid acid contents in the cell membranes were measured. Furthermore, LTR (long terminal repeat)-amplicon sequencing was used to profile yeast transposon activities in the treatments. The results showed the Del type had a higher survival rate, biomass, and ethanol production, revealing negative correlations between spt23 expression levels and thermal tolerance. Total unsaturated lipid acid (TULA) contents in cell membranes were lower in the Del type, indicating its negative association with spt23 expression levels. The Del type resulted in the lower richness and higher evenness in LTR distributions, as well as higher transposon activities. The intersection of 3 gene sets and regression analysis revealed the relative weight of spt23's direct and TY-induced influence is about 4:3. These results suggested a heat tolerance model in which spt23 increases cell thermal tolerance through transcriptional regulation in addition to spt23-transposon triggered unknown responses. KEY POINTS: • spt23 is a key gene for heat tolerance, important for LA contents but not vital. • Deletion of spt23 decreases in yeast's LTR richness but not in evenness. • The relative weight of spt23's direct and TY-induced influence is about 4:3.
spt23 在出芽酵母的耐热性中发挥多种作用。spt23 调节细胞内不饱和脂肪酸 (ULA) 的含量，这会显著影响细胞的耐热性。作为 Ty 抑制剂，spt23 还可以与转座子（Tys）相互作用，这些转座子是酵母适应性进化的贡献者。然而，很少有研究调查 spt23 是否以及在多大程度上可以通过转座子发挥其调节功能。在这项研究中，对耐热酿酒酵母菌株进行了表达数量性状基因座 (eQTL) 分析，发现 spt23 是突变体中最重要的基因之一。构建了 spt23 过表达 (OE)、缺失 (Del) 和整合表达 (IE) 菌株。测量了它们的耐热性、乙醇产量、关键基因的表达水平以及细胞膜中脂质酸的含量。此外，还使用 LTR（长末端重复）扩增子测序来分析处理中酵母转座子活性。结果表明，Del 型的存活率、生物量和乙醇产量更高，表明 spt23 表达水平与耐热性呈负相关。细胞膜中总不饱和脂质酸 (TULA) 含量较低，表明其与 spt23 表达水平呈负相关。Del 型导致 LTR 分布的丰富度降低而均匀度增加，以及转座子活性增加。3 个基因集的交集和回归分析揭示了 spt23 的直接和 TY 诱导影响的相对权重约为 4:3。这些结果表明了一种耐热性模型，其中 spt23 通过转录调控增加细胞的耐热性，除了 spt23-转座子触发的未知反应外。关键点： • spt23 是耐热性的关键基因，对 LA 含量很重要，但不是必需的。 • spt23 的缺失降低了酵母 LTR 的丰富度，但不影响均匀度。 • spt23 的直接和 TY 诱导影响的相对权重约为 4:3。
