The 30th International Conference on Arabidopsis Research (ICAR 2019)

450 / 2019-02-25 16:14:02

The Transcriptional Feedforward Loop Consisting of Dof2.1 and MYC2 Enhances Jasmonate Responses in Arabidopsis thaliana

jasmonate,Dof,MYC2,transcription factor

Plenary track > Hormones

Dof proteins are plant-specific transcription factors with a highly conserved DNA-binding with one finger (Dof) domain. Arabidopsis possesses 37 Dof genes, some of which have been shown to play a variety of roles in the regulations of plant-specific biological processes. In this study, we show the vital role of Dof2.1 in JA responses in Arabidopsis. RT-qPCR analysis revealed that the expression of Dof2.1 is strongly induced by methyl jasmonate (MeJA). Phenotypic analysis of the dof2.1 knockout mutant (dof2.1-KO) and transgenic plants overexpressing Dof2.1 (Dof2.1-OX) revealed that the disruption and overexpression of Dof2.1 exert opposite effects on leaf senescence and root growth, particularly when MeJA is present, suggesting that Dof2.1 might act as an enhancer of JA responses. Transcriptome analysis using the dof2.1-KO and Dof2.1-OX plants revealed that Dof2.1 strongly affects the expression level of MYC2 encoding the master regulator of JA responses. Furthermore, ChIP-qPCR analysis and co-transfection assay revealed that Dof2.1 directly activates MYC2, while MYC2 also directly activates Dof2.1. Based on these findings, we propose that Dof2.1 and MYC2 form a transcriptional feedforward loop for the enhancement of JA responses. We show further evidence for this loop by phenotypic characterization with the myc2 knockout mutant overexpressing Dof2.1 and the dof2.1-KO mutant overexpressing MYC2. We discuss the significance of the Dof2.1-MYC2 feedforward loop in JA responses.