Combining of transcriptome and metabolome analyses for understanding the utilization and metabolic pathways of Xylo-oligosaccharide in ATCC 15703.

A combination of transcriptome and metabolome analyses was applied to understand the utilization and metabolism of Xylo-oligosaccharide (XOS) in 15703 as well as identifying the key regulatory-related genes and metabolites. Samples of cultures grown on either XOS or xylose were collected. The transcript and metabolite profiles were obtained from high-throughput RNA-sequencing data analysis and UHPLC system. Compared with xylose, XOS highly promoted the growth of 15703 and resulted in a growth yield about 1.5-fold greater than xylose. The transcriptome analysis showed that XOS could enhance genes, including ABC transporters, galactosidase, xylosidase, glucosidase, and amylase, which were involved in transport and metabolism of carbohydrate compared with xylose. Furthermore, the expression profile of 16 candidate genes using qRT-PCR has validated the accuracy of the RNA-seq data. Also, the metabolomic analyses, particularly those related to metabolic biomarkers of fatty acids, amino acids, and sugars showed a similar trend of result and approved the advantages of XOS as growth medium for 15703 compared with xylose. The expression and abundance of specific genes and metabolites highlighted the complex regulatory mechanisms involved in utilization of XOS by 15703. These results are useful in the understanding of the metabolic pathway of XOS in 15703 and contribute to the optimization of XOS probiotic effects as a food additive.