Transcriptomics Analysis Of Saccharomyces Cerevisiae Under Calcium Propionate

As a food additive,calcium propionate is added to fermented foods(such as bread)to prolong shelf life by inhibiting the growth of microorganisms(such as mold).At present,most of the researches about the antiseptic effect of calcium propionate focus on its antiseptic effect during food storage.However,the molecular mechanism of calcium propionate on yeast during the production of bread and other fermented foods is rarely reported.High-sugar-tolerant yeast BH1 is a yeast that can maintain good proliferation and fermentation capacity though there are in an environment with high-sugar concentration.The RNA-Seq technology was used to preliminary explore the response mechanism of this yeast strain to calcium propionate stress,and by analyzing the differentially expressed genes(DEGs)under different calcium propionate stress conditions,some key genes for yeast cells to respond to calcium propionate stress were found,then the molecular regulation mechanism of calcium propionate to inhibit yeast proliferation was preliminarily deduced,which proves scientific basis and theoretical guidance for optimizing calcium propionate-resistant strains.The main results of this study are as follows:(1)Calcium propionate has an inhibitory effect on the growth of high-sugar resistant yeast BH1.The study found that the main inhibitory effect of calcium propionate on yeast is propionate.0.25% mass fraction of calcium propionate has a significant inhibitory effect on yeast growth.(2)Under calcium propionate,the expression of a series of genes in high glucose resistant yeast BH1 cells changed.Compared with the control group,there were 1438 DEGs in the calcium propionate 2 h experimental group,of which 643 genes were up-regulated and 795 genes were down-regulated.DEGs involve ribosomes,carbon metabolism,amino acid biosynthesis,purine metabolism,MAPK signaling pathways,meiosis,cell cycle,glycolysis,pyrimidine metabolism,spliceosome,and eukaryotic ribosomal biosynthesis.(3)Under calcium propionate,DNA and cell wall proteins in yeast cells will be damaged to a certain extent.Down-regulated expression of cyclin genes CLB1,CLB2 and CLN2 makes the cell cycle more delayed in G1 phase;at the same time,the synthesis of amino acids is affected,the synthesis of protein by ribosomes is inhibited;the synthesis of mannose protein(at the outer layer of the cell wall)is also inhibited,which greatly limits the proliferation of cells.(4)Under calcium propionate,although the energy synthesis in the yeast cells is accelerated,the distribution and utilization of energy and the normal metabolic activities have changed greatly.The rate of glycolysis is accelerated,the process of TCA is enhanced,and cells accelerate the synthesis and utilization of ATP;PMA1 and PDR12 and other genes up-regulate to maintain intracellular p H homeostasis and accelerate proton pumping.