Integrated transcriptomics and metabolomics unravel the metabolic pathway variations for barley β-glucan before and after fermentation with DY-1.

The results of our previous study showed that the structure and function of β-glucan in barley were changed after fermentation by L. DY-1. In this study, the antioxidant activities of RBG (regular barley β-glucan, unfermented) and FBG (barley β-glucan, fermented with L. DY-1) were evaluated by adopting an animal model, (). We also carried out an integrated transcriptomic and metabolomic profiling for RBG and FBG to delineate their signature pathways. RBG treatment has better effects on SOD enzyme activity and ROS levels than FBG, while FBG treatment has better effects on the CAT enzyme activity and MDA content than RBG in . Transcription group analysis showed that FBG mainly decreases the expression of the gene to inhibit the calcium signaling pathway, promotes the Wnt signaling pathway by up-regulating the gene and improving the oxidative damage of ; RBG mainly inhibits calcium signal pathways by reducing the expression of ANT-solute carrier family 25 genes, promoting life adjustment pathways by reducing the expression of the gene to improve the oxidative stress of . Joint analysis showed that the difference between FBG and RBG in the regulation of oxidative stress is mainly reflected in the metabolism pathway of arachidonic acid. Under the regulation of FBG, the expression of the gene was decreased, the expression of leukotriene A4, prostaglandin G2, arachidonic acid and phosphatidylcholine was decreased, and the expression of 14,15-DiHETrE was increased. Under the regulation of RBG, the expression of gene was up-regulated, the expression of metabolites such as leukotriene B4 was up-regulated, and the expression of arachidonic acid and phosphatidylcholine was down-regulated.