GC/MS-based metabolomic studies reveal key roles of glycine in regulating silk synthesis in silkworm, Bombyx mori

Metabolic profiling of silkworm, especially the factors that affect silk synthesis at the metabolic level, is little known. Herein, metabolomic method based on gas chromatography-mass spectrometry was applied to identify key metabolic changes in silk synthesis deficient silkworms. Forty-six differential metabolites were identified in Nd group with the defect of silk synthesis. Significant changes in the levels of glycine and uric acid (up-regulation), carbohydrates and free fatty acids (down-regulation) were observed. The further metabolomics of silk synthesis deficient silkworms by decreasing silk proteins synthesis using knocking out fibroin heavy chain gene or extirpating silk glands operation showed that the changes of the metabolites were almost consistent with those of the Nd group. Furthermore, the increased silk yields by supplying more glycine or its related metabolite confirmed that glycine is a key metabolite to regulate silk synthesis. These findings provide important insights into the regulation between metabolic profiling and silk synthesis. [Display omitted] •Silk synthesis defective silkworms were got through extirpating silk glands, knocking out fib-H gene and natural mutant.•There are sixteen differential metabolites detected in all selected silkworms based on metabolomic analysis.•Differential metabolites involved in amino acid metabolism, glycolysis, pentose phosphate pathway and so on.•Important metabolites (glycine, ACPC) were injected into silkworms to confirm the key roles in regulating silk synthesis.