Integrated analysis of transcriptome, proteome and non-targeted metabolome for exploring the mechanism of selenium biotransformation in Pichia kudriavzevii

Pichia kudriavzevii could resist high concentrations of sodium selenite and efficiently biotransform over 80% of the absorbed selenium. However, the specific molecular mechanisms underlying this biotransformation remain unclear. This study aimed to investigate the mechanism of selenium biotransformation focusing on selenium transport, detoxification, reduction, and the formation of organic selenium compounds through a comprehensive approach combining transcriptomic, proteomic, and non-targeted metabolomic analyze. Results showed that the JEN1 gene was responsible for selenium transport, while the upregulation of cysJ, , CYSK, , TRXB1 and sat genes as well as the involvement of glutathione, are crucial for the accumulation of organic selenium. Furthermore, GSTY2, , TRXB1 and GPX3 were pivotal genes in Se(IV) reduction and their corresponding proteins were key proteins. Additionally, the enhanced expression of genes related to antioxidant enzymes ( GSTY2 , TRXB1, , and GPX3), ), ABC transports, heat shock proteins and antioxidant enzymes proteins (GSTY2, TRXB1, and GPX3) collectively contributed to selenium tolerance, detoxification and protection against oxidative damage. GO and KEGG analysis highlighted alterations in amino acid metabolism, carbohydrate metabolism, and energy metabolism in the selenium biotransformation process. These findings provide novel insight into the mechanisms of selenium biotransformation in P. kudriavzevii and its application in the fields of the food industry.