Broadly targeted metabolomics study of highland barley seeds of different qualities
Three representative highland barley of good quality,medium quality and poor quality were selected from 81 Tibetan highland barley according to the content of quality indexes(protein,starch,β-glucan,γ-ami-nobutyric acid).'Biru'highland barley was selected as the good quality,'Qushui'highland barley was selected as the medium quality and'Baribai'highland barley was selected as the poor quality.The changes of metabolites in barley seeds of different quality were studied by LC-MS/MS.The total number of differentially expressed metab-olites between'Biru'and'Baribai'(56 up-regulated,206 down-regulated),'Biru'and'Qushui'(179 metab-olites up-regulated,82 down-regulated),'Qushui'and'Baribai'(58 up-regulated,240 down-regulated)was 262,261 and 298,respectively.Difference fold analysis found that phenolic acids was the main metabolite of the high quality compared with the low quality,and anthocyanins was the main metabolites of the high quality compared with the medium quality.The results of metabolic pathway enrichment analysis showed that the differential metabo-lites of high quality were enriched in 65 pathways,mainly in amino acid biosynthesis,aminoacyl biosynthesis and flavonoid biosynthesis.Compared with medium quality,the up-regulated differential metabolites of high quality were enriched in 65 pathways,mainly in amino acid biosynthesis,aminoacyl biosynthesis and 2-oxy-cyclopentane meth-yl ester metabolism.Compared with the low quality,the differential metabolites of medium quality were enriched in 61 pathways,mainly including biosynthesis of flavonoids and flavonols,purine metabolism,pyrimidine metabolism and aminoacyl biosynthesis.