A Jasmonate-Activated MYC2-Dof2.1-MYC2 Transcriptional Loop Promotes Leaf Senescence in Arabidopsis.

DNA binding-with-one-finger (Dof) proteins are plant-specific transcription factors closely associated with a variety of physiological processes. Here, we show that the Dof protein family in Arabidopsis () functions in leaf senescence. Disruption of , a jasmonate (JA)-inducible gene, led to a marked reduction in promotion of leaf senescence and inhibition of root development as well as dark-induced and age-dependent leaf senescence, while overexpression of promoted these processes. Additionally, the knockout mutant showed almost no change in the transcriptome in the absence of JA; in the presence of JA, expression of many senescence-associated genes, including , which encodes a central regulator of JA responses, was induced to a lesser extent in the mutant than in the wild type. Furthermore, direct activation of the promoter by Dof2.1, along with the results of epistasis analysis, indicated that Dof2.1 enhances leaf senescence mainly by promoting expression. Interestingly, MYC2 was also identified as a transcriptional activator responsible for JA-inducible expression of Based on these results, we propose that Dof2.1 acts as an enhancer of JA-induced leaf senescence through the MYC2-Dof2.1-MYC2 feedforward transcriptional loop.