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

During postharvest life, broccoli suffers from florets yellowing, which reduces its economic and nutritional value. We investigated the mechanisms employed by exogenous phytosulfokine alpha (PSK alpha) applying at 150 nM for delaying senescence in broccoli florets stored at 4 degrees C for 28 days. The results showed that the SnRK1 gene expression was higher in broccoli florets treated with 150 nM PSK alpha, 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 PSK alpha. Taken together, our results assume that exogenous PSK alpha application as signaling bioactive peptide could be considered as a promising procedure for delaying senescence of broccoli florets during cold storage.

Automated summary

The study showed that treatment with 150 nM PSK alpha can delay senescence in broccoli florets by increasing the expression of SnRK1 gene and enhancing the activity of H+-ATPase, Ca2+-ATPase, SDH, and CCO. Additionally, higher expression of AOX and UCP1 genes can reduce H2O2 accumulation, while lower mPTP opening can prevent ROS accumulation in broccoli florets.