Genetic Strategies and Mechanisms for Improving Ribonucleic Acid Levels of <i>Saccharomyces pastorianus</i>

Developing microorganisms with a high ribonucleic acid (RNA) content is crucial for the RNA industry. Numerous studies have been conducted to enhance RNA production in yeast cells through genetic engineering, yet precise mechanisms remain elusive. Previously, upregulation of <i>TAL1</i> or <i>PGM2</i> and deleting <i>PRS5</i> or <i>DBP8</i> individually could increase the RNA content in <i>Saccharomyces pastorianus</i>. In this study, within these genetically modified strains, the intracellular nucleotide levels notably increased following cell fragmentation. Deletion of <i>PRS5</i> and <i>DBP8</i> within the strain prompted the upregulation of genes sharing similar functions, consequently augmenting the flow of the gene pathway. Furthermore, the upregulation of genes encoding cell-cycle-dependent protein kinases (CDK) was observed in the G03-△PRS5 strain. The influence of <i>TAL1</i> and <i>PGM2</i> on RNA content was attributed to the pentose phosphate pathway (PPP). The RNA content of polygenic recombinant strains, G03-△PRS5+△DBP8 and G03-△PRS5+△DBP8+PGM2, displayed the most significant improvement, increasing by 71.8 and 80.1% when compared to the parental strain. Additionally, the maximum specific growth rate of cells increased in these strains. This study contributes valuable insights into the genetic mechanisms underlying high nucleic acid synthesis in <i>S. pastorianus</i>.