Ripening inhibitory effect of the ethylene signalling protein EIN2 derived octapeptide NOP-1 on tomatoes as influenced by repeated applications and applications at different ripening stages

Abstract The synthetic octapeptide NOP-1 inhibits ethylene downstream signalling by disrupting the ETR1- EIN2 interaction, resulting in ripening delay of tomatoes when applied at early ripening stages. In order to better understand the NOP-1 induced ripening delay, we investigated the effect of a repeated surface application of NOP-1 as well as its application at advanced maturity stages of tomatoes. For this, analytic and non-destructive evaluation parameters were used. NOP-1 delayed ripening when applied at the maturity stage breakers (BR) as indicated by colour development. Repeated application had no additional delaying effect and did not reach the level of ripening delay induced by 1-MCP. When applied at maturity stage pink (PI), no ripening delay was observed, indicating that NOP-1 works best when applied at early ripening stages, long before autocatalytic ethylene synthesis takes place. In conclusion, peptide-based impairment of ethylene signalling offers new possibilities for ripening control of climacteric fruits. Thereby, method and timing of peptide application need to be considered.