S-alk(en)ylcysteine sulfoxides biosynthesis and free amino acids profile in different parts of postharvest chive (Allium schoenoprasum L.)

The purpose of this study was to investigate the dynamics in S-alk(en)ylcysteine sulfoxides (CSOs) biosynthesis and free amino acids (FAA) accumulation and remobilization in different parts of chive during postharvest storage. The chives were stored for 5 days at 20 degrees C (RT) and 20 days at 3 degrees C (LT). The CSOs and most of the FAA accumulated in the bottom-white part (BW) during chive senescence in the round-green part (RG) during the storage. There was a strong correlation (0.750.96, P<0.001) between the CSOs and FAA changes in the RG and the BW of the chive. In the BW of the chive, the total CSOs content increased by 17.53 % under RT and 38.06 % under LT storage, while the content of total FAA increased by 443 % under RT and 464 % during LT storage. However the CSOs and FAA changed much less in the RG of the chive during the storage. The FAA, glutathione Stransferase (GST) and gamma-glutamyl dipeptidase (GGT) results further indicated that the CSOs were biosynthesized in whole parts but much higher in the BW part during storage. The product of proteolysis (Met and Ser) provided the material for the biosynthesis of CSOs via Cys the pathway. The change in the CSOs and FAA profile in RG and BW of chive during storage was through a source-to-sink transition phenomenon, which resulted in the remobilization of the nutrient (S and N) from the RG to BW parts of the chive. The LT storage increased CSOs accumulation by prolonging the storage time, delayed FAA accumulation by inhibiting proteolysis and increased protein content in the BW during the storage. Our study's results provide new insight into the CSOs biosynthesis of postharvest chive and the role of storage temperatures on S-alk(en)ylcysteine sulfoxides biosynthesis and FAA remobilization in postharvest chive.

Automated summary

The study investigates the biosynthesis of S-alk(en)ylcysteine sulfoxides (CSOs) and accumulation of free amino acids (FAA) in chives during postharvest storage. The CSOs and FAA accumulation mainly occur in the bottom-white part of the chives during senescence and storage. There is a strong correlation between CSOs and FAA changes in different parts of the chives. LT storage leads to increased CSOs accumulation and delayed FAA accumulation.