A chemical approach to extend flower longevity of Japanese morning glory via inhibition of master senescence regulator EPHEMERAL1

Petal senescence in flowering plants is a type of programmed cell death with highly regulated onset and progression. A NAM/ATAF1,2/CUC2 transcription factor, EPHEMERAL1 (EPH1), has been identified as a key regulator of petal senescence in Japanese morning glory (Ipomoea nil). Here we used a novel chemical approach to delay petal senescence in Japanese morning glory by inhibiting the DNA-binding activity of EPH1. A cell-free high-throughput screening system and subsequent bioassays found two tetrafluorophthalimide-based compounds, Everlastin1 and Everlastin2, that inhibited the EPH1–DNA interaction and delayed petal senescence. The inhibitory mechanism was due to the suppression of EPH1 dimerization. RNA-sequencing analysis revealed that the chemical treatment strongly suppressed the expression of programmed cell death- and autophagy-related genes. These results suggest that a chemical approach targeting a transcription factor can regulate petal senescence.