Basil chilling injury: Oxidative stress or energy depletion?

Abstract

Basil (Ocimum basilicum L.) is susceptible to chilling injury (CI), leading to significant postharvest quality loss. This research aimed to identify key metabolites involved in CI of basil during cold storage to better understand the underlying mechanisms. Metabolite profiles of basil leaves stored at 4 and 12 °C for up to 12 days were quantified by ¹H NMR and GC–MS. At 4 °C shelf life was reduced due to CI. At 4 °C, several osmoprotectants, including proline, gamma-aminobutyric acid, trehalose and myo-inositol increased, whereas antioxidants like ascorbic acid and rosmarinic acid decreased; the latter likely due to scavenging reactive oxygen species. During chilling stress, antioxidant defence pathways were upregulated and carbohydrate related energy pathways were downregulated. We suggest that CI in basil associates with redirection of carbohydrate flux towards antioxidant defence systems, leading to energy depletion. This energy depletion is hypothesized as a primary trigger for CI in postharvest basil.