Trypsin preservation: CsUGT91C1 regulates Trilobatin Biosynthesis in Cucumis sativus during Storage

Trypsin can significantly improve the storage quality of Cucumis sativus ( C. sativus ) due to its novel superoxide scavenging activity. Based on the results of physiological indices, an integrated analysis of widely targeted metabolomics and transcriptomics was carried out, gene function was further confirmed by VIGS, a potential molecular mechanism of resistance improvement of C. sativus due to flavonoid biosynthesis induced by trypsin was proposed and discussed. Transcriptomic results showed that 1,068 genes highly related to flavonoid biosynthesis gathered in the brown module were obtained by the advanced method WGCNA. An isomeric compound of dihydrochalcone, trilobatin, was likely to be the key metabolite regulated by trypsin. Results of O2PLS and co-expression network illustrated that CsUGT91C1 acted as the hub gene which regulated the biosynthesis of flavonoids, especially trilobatin, in C. sativus . CsUGT91C1 also played as a hub node in the Protein-Protein Interactions network of WGCNA screened genes (WSGs). GO and KEGG analyses of WSGs enriched the transferase activities, especially UDP-glycosyltransferase activity and KEGG pathways of “Phenylpropanoid biosynthesis (map00940)” and “Flavonoid biosynthesis (map00941)”. Results of webtools of the PlantCARE database identified the G-box region of CsUGT91C1 , which can bind to the transcription factor CsMYC2. The expression and biological effects of CsUGT91C1 were significantly impeded by the silencing of CsMYC2 through VIGS. The results of this study might give new insight into the exploration of the postharvest resistance mechanism of C. sativus induced by trypsin and provide useful information for the subsequent mining of resistance genes in C. sativus . Graphical abstract