The Function Of FKS Family Genes On The Yeast Cells Morphology And Anti-autolytic Ability

Saccharomyces cerevisiae have signicicant value in industrial manufacture such as brewing,pharmacy and food industry,it is also a representative model organism in eucaryon research.In the industrial manufacture,the S.cerevisiae autolysis have bad influcance on the products quality.For example,if the autolysis of S.cerevisiae in beer brewing used come about,the beer could have a strong undesirable flavor.The cell wall is the cells' most important structural,the function the cell wall including maintain the cell structural,resistance the environment mechanical pressure,keep the cells' osmotic balance.?-1,3-glucan is the most important structurel of cell wall,and FKS family genes is responsibility for encode ?-1,3-glucan synthase.Inorder to demonstrate the the function of the ?-1,3-glucan for cells' physiological property,and it is necessary to make the internal mechanism and factors that control the yeast autolysis clear.I constructed the recombination strains by knocked out FKS family genes.Then compared the cell wall morphology,the cell wall composition,the cells' resisitance of autolysis,the capacity to environmental stress and the condition related genes' expression.The main results of this study were listed as follows:(1)Contrasnt the the recombination strains.The FKS1 gene and FKS2 gene knocked out strains were used as wild type strains,the uracil and histidine were used as selection of auxotrophic to knocked out FKS2 and FKS3 genes.Finally,the FKS1,FKS2 genes knocked out strain,the FKS1,FKS3 genes knocked out strain,the FKS2,FKS3 genes knocked out strain and the FKS1,FKS2,FKS3 genes knocked out strains were constructed.The strains were namely sequencly by fks1,2-QT,fks1,3-QT,fks2,3-Q and fks1,2,3-QT.(2)Anlysis the cell morphology of the recombination strains.The single knocked out of FKS family genes did not effect the cell's morphology.When FKS1 and FKS2 genes were both knocked out,the morphology of the strains changed obviously.The wild type strain was spherical,while the shape of mutant strains fks1,2-QT and fks1,2,3-QT became ellipsoidal.The volume of mutant strains fks1,2-Q and fks1,2,3-QT was reduced by 71.2% and 74.2% compared to that of wild type W303.Hence,the FKS1 and FKS2 genes controlled the cells' morphology together.(3)The effect of FKS family genes on the cell wall polysaccharides.The FKS family genes were responsibility for the ?-1,3-glucan sythensis.The thickness of cell wall of fks1,2-QT reduced by 49% compared to that of wild type strain,and its cotent of ?-1,3-glucan in cell wall reduced by 60%.Demonstrate that FKS1 gene played an important role in sythysis the ?-1,3-glucan and matain the cell wall.The cotent of ?-1,3-glucan of fks2-Q and fks3-QT was similarly with that of W303,therefore the FKS2 and FKS3 gene barely effect the synthesis of ?-1,3-glucan.Furthermore,the FKS family genes was indifference.Especically the FKS1 and FKS2 genes,and the strains' cotent of ?-1,3-glucan was increased.There maybe consisit compensation mechanism to sythsis ?-1,3-glucan.(4)The effect of FKS family genes on the cells' anti-autolytic ability.In the simulated autolytic silution,the anti-autolitic ability of mutant strains fks1,2-Q and fks1,2,3-QT was worst,their autolysis condition and mortality rate was much higher than other strains.Therefore,the FKS1 gene played an important role in cells' anti-autolytic ability.The anti-autolitic ability of mutant strain fks3-QT was better than wild type strains,the strains WSC2 and MSN4 genes expression were up regulated by 6.88 and 5.25 compared to wild type strain W303.The function of WSC2 and MSN4 genes was stress-responsive transcription activator.The cells become more sensitive to the environment due to the two genes' up regulation,which make the cell could regulated the cells quickly.