Comparative transcriptome analysis of salt tolerance mechanism of Meyerozyma guilliermondii W2 under NaCl stress.

A high-salt-tolerant strain, Meyerozyma guilliermondii, has been isolated from activated sludge which has a great effect in the treatment of high-salt wastewater. To identify the salt tolerance mechanism of the strain, transcriptome sequencing and fluorescence quantitative PCR were used to analyse and compare the thallus, which were growing in the salt-free, low-salt (4%), and high-salt (16%) YPD media for 48 h, respectively, and then the change of intracellular and extracellular glycerol was determined. The results showed that 8220 unigenes were obtained from the sequencing data after de novo splicing, among which 6334 genes had annotation information in the SwissProt library. With salt-free as reference, there were 1135 unigenes that differentially expressed under low-salt stress and 1948 unigenes were differentially expressed under high-salt stress. With low salt as reference, 3056 unigenes were differentially expressed under high-salt stress. The fluorescence quantification results of the six candidate genes selected in this study were consistent with the transcriptome data. Under high-salt stress, the intracellular glycerol of M. guilliermondii reached a maximum value at about 10 min, then decreased quickly and tended to be stable. This study provided valuable data for the next study of salt tolerance of M. guilliermondii, and also contributed to the functional study of yeast salt tolerance genes.