Exogenous application of phytosulfokine α (PSKα) delays senescence in broccoli florets during cold storage by ensuring intracellular ATP availability and avoiding intracellular ROS accumulation

Abstract

Abstract During postharvest life, broccoli suffers from florets yellowing, which reduces its economic and nutritional value. We investigated the mechanisms employed by exogenous phytosulfokine α (PSKα) applying at 150 nM for delaying senescence in broccoli florets stored at 4 °C for 28 days. The results showed that the SnRK1 gene expression was higher in broccoli florets treated with 150 nM PSKα, which may warrant sufficient intracellular availability of ATP, resulted from a higher activity of H+-ATPase, Ca2+-ATPase, succinate dehydrogenase (SDH), and cytochrome c oxidase (CCO). In addition, avoiding H2O2 accumulation by higher expression of alternative oxidase (AOX) and uncoupling protein (UCP1) genes may arise from higher SnRK1 gene expression. Additionally, lower mitochondrial permeability transition pore (mPTP) opening may avoid ROS accumulation in broccoli florets treated with 150 nM PSKα. Taken together, our results assume that exogenous PSKα application as signaling bioactive peptide could be considered as a promising procedure for delaying senescence of broccoli florets during cold storage.