Endogenous phytosulfokine α (PSKα) signaling delays petals senescence and prolongs vase life of cut rose flowers (Rosa hybrida cv. Angelina)

This study investigated the endogenous phytosulfokine alpha (PSK alpha) signaling during opening and senescence in rose flowers. Our results showed that the higher phytosulfokines (PSKs) and tyrosyl protein sulfotransferase (TPST) expression could be responsible for higher endogenous PSK alpha accumulation in petals during rose flowers opening (stages 2 and 3). By triggering the endogenous PSK alpha signaling, higher phytosulfokine receptor 1 (PSKR1) expression could be responsible for higher cytosolic cyclic guanosine monophosphate (cGMP) accumulation in petals during rose flowers opening (stages 3 and 4). Higher protein kinase G (PKG) and cyclic nucleotide-gated ion channel 1 (CNGC1) expression accompanying higher plasma membrane intrinsic protein 2 (PIP2) and tonoplast intrinsic protein 1 (TIP1) expression in petals during rose flowers opening may arise from higher cytosolic cGMP accumulation giving rise to higher petals relative water content (RWC) (stage 4). Triggering phosphodiesterase (PDE) expression lay off cytosolic cGMP signaling. Suppressing PKG and CNGC1 expression accompanying lower PIP2 and TIP1 expression accelerates petals senescence in rose flowers representing by deteriorating petals membrane integrity revealed by higher electrolyte leakage and malondialdehyde (MDA) accumulation (stage 5 and 6). For delaying petals senescence and prolonging vase life in cut rose flowers, we employed exogenous PSK alpha treatment at the commercial harvest stage (stage 3). Our results showed that the suppressing PDE expression in petals by exogenous 150 nM PSK alpha treatment could be responsible for allowing cytosolic cGMP signaling ongoing for supporting PKG and CNGC1 expression accompanying by higher PIP2 and TIP1 expression. Exogenous 150 nM PSK alpha treatment, outperforming cut rose flowers by delayed senescence and prolonged vase life to 16 days from 12 days could be ascribed to preserving membrane integrity revealed by lower electrolyte leakage and MDA accumulation. Our results could be proposed that exogenous PSK alpha treatment and endogenous PSK alpha signaling for employing in the floriculture industry for delaying petals senescence and prolonging the vase life of cut rose flower.

Automated summary

The study found that endogenous PSK alpha signaling affects the physiological activities of rose petals during flower opening by regulating PSKR1 and cGMP accumulation, delaying senescence. On the other hand, during flower senescence, PDE expression inhibits cGMP signaling, accelerating petal aging.