Study Of Salt Tolerance Mechanism In Aureobasidium Pullulans

Black Yeast is a yeast-like fungus that produces melanin inside and outside the cell wall.It is one of the most salt-tolerant eukaryotes.Their main features are polymorphism,synthetic melanin and extracellular polysaccharides.It is not clear whether these factors are related to its high salt tolerance.Aureobasidium pullulans has the above characteristics.It provides an important model for this scientific question.Black yeast isolated from strawberry: A.pullulans NG will be used as the experimental material.We will detect the characteristics of growth,cell differentiation phenotype,accumulations under different salt concentrations.Explore the molecular biological mechanism of salt tolerance by transcriptomics and the conclusions are as follows:(1)Aureobasidium pullulans responds to Na Cl stress through cell differentiation.Under salt stress conditions,the cells differentiate into swollen cells that resist Na Cl stress and propagate through multi-terminal budding.At low salt concentrations(<9% Na Cl),the cells can differentiate into hyphae to escape from unfavorable environments.At high salt concentrations,the cells differentiate into swollen cells,septate swollen cells and Monilioid hyphaes.(2)Aureobasidium pullulans can resist high osmotic stress by accumulating glycerol,and the accumulation of glycerol is positively correlated with the concentration of Na Cl.The intracellular accumulation of glycerol fluctuates with the cultivation time,and the degree of fluctuation is linearly related to the Na Cl concentration.The cells balance cell growth and salt stress adaptation by adjusting the consumption of glycerol.A.pullulans NG does not synthesize trehalose to resist osmotic stress.(3)Through transcriptome sequencing analysis of 7% salt stress treatment and control,1558 different expressed genes were found,of which 817 genes were up-regulated and 741 genes were down-regulated.6 KEGG pathways involved in salt stress response.The number of different genes in the KEGG pathway involved in the response to salt stress are: 7(4 up-regulated,3 down-regulated)in the Glycerolipid metabolism pathway;6(1 Up-regulation,5 down-regulation)in the MAPK signaling pathway-yeast;17(9 up-regulation,8 down-regulation)in the starch and sucrose metabolism,9(6 up-regulated,3 down-regulated)in the arginine and proline metabolism,13(8 up-regulated,5 down-regulated)in the tryptophan metabolism pathways;7(4 up-regulated,3 down-regulated)in the Glycine serine and threonine metabolism.Screened out 7 genes related to glycerol synthesis,4 genes were up-regulated and 3 genes were down-regulated.These genes are closely related to cell energy metabolism and growth metabolism.