State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A&F University, Lin'an, Hangzhou, 311300, China.
Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, SE-413 90, Goteborg, Sweden.
BMC Genomics. 2022 Jul 15;23(1):514. doi: 10.1186/s12864-022-08742-y.
Ammonium is an important raw material for biomolecules and life activities, and the toxicity of ammonium is also an important ecological and agricultural issue. Ammonium toxicity in yeast has only recently been discovered, and information on its mechanism is limited. In recent years, environmental pollution caused by nitrogen-containing wastewater has been increasing. In addition, the use of yeast in bioreactors to produce nitrogen-containing compounds has been developed. Therefore, research on resistance mechanisms that allow yeast to grow under conditions of high concentrations of ammonium has become more and more important.
To further understand the resistance mechanism of yeast to grow under high concentration of ammonium, we used NHCl to screen a yeast non-essential gene-deletion library. We identified 61 NHCl-sensitive deletion mutants from approximately 4200 mutants in the library, then 34 of them were confirmed by drop test analysis. Enrichment analysis of these 34 genes showed that biosynthesis metabolism, mitophagy, MAPK signaling, and other pathways may play important roles in NHCl resistance. Transcriptome analysis under NHCl stress revealed 451 significantly upregulated genes and 835 significantly downregulated genes. The genes are mainly enriched in: nitrogen compound metabolic process, cell wall, MAPK signaling pathway, mitophagy, and glycine, serine and threonine metabolism.
Our results present a broad view of biological pathways involved in the response to NHCl stress, and thereby advance our understanding of the resistance genes and cellular transcriptional regulation under high concentration of ammonium.
氨是生物分子和生命活动的重要原料，其毒性也是一个重要的生态和农业问题。酵母中的铵毒性最近才被发现，其机制的信息有限。近年来，含氮废水造成的环境污染不断增加。此外，酵母在生物反应器中用于生产含氮化合物的应用也得到了发展。因此，研究允许酵母在高浓度铵条件下生长的抗性机制变得越来越重要。
为了进一步了解酵母在高浓度铵条件下生长的抗性机制，我们使用 NHCl 筛选酵母非必需基因缺失文库。我们从文库中的大约 4200 个突变体中鉴定出 61 个对 NHCl 敏感的缺失突变体，然后通过滴度测试分析确认了其中的 34 个。对这 34 个基因的富集分析表明，生物合成代谢、线粒体自噬、MAPK 信号通路等途径可能在 NHCl 抗性中发挥重要作用。NHCl 胁迫下的转录组分析显示 451 个显著上调基因和 835 个显著下调基因。这些基因主要富集在：氮化合物代谢过程、细胞壁、MAPK 信号通路、线粒体自噬和甘氨酸、丝氨酸和苏氨酸代谢。
我们的结果提供了对参与 NHCl 应激反应的生物学途径的广泛了解，从而加深了我们对高浓度铵下抗性基因和细胞转录调控的理解。
