Synthesis of 1-aminocyclopropane-1-carboxylic acid peptide analogues and evaluation of their ethylene physiological effects

Peptide pesticides have become a research hotspot in pesticide science owing to their high activity, precise target selectivity, and environmental friendliness. Based on the unique structure of 1-aminocyclopropane-1-carboxylic acid (ACC), 16 linear oligomeric ACC peptide derivatives along with 3 cyclic dipeptide derivatives were designed and synthesized in this study. Their structures were confirmed by ¹H NMR, ¹³C NMR, and HRMS. The ethylene physiological effects of the target compounds were evaluated by observing the "triple response" phenomenon in etiolated pea seedlings. The results showed that some compounds induced ethylene response phenotypes in pea seedlings and this induction was concentration-dependent. Among them, 6a exhibited the most prominent activity. At a test concentration of 0.5 mmol/L, 6a showed a stem growth inhibition rate of 21.23% and an epicotyl thickening rate of 15.38%, which were slightly higher than those of the control agent ACC. Furthermore, a preliminary structure-activity relationship analysis was conducted based on the evaluation results of their ethylene physiological effects. These findings provide a theoretical basis for the further development of ACC analogs and novel peptide pesticides.