Interaction between MYC2 and ETHYLENE INSENSITIVE3 Modulates Antagonism between Jasmonate and Ethylene Signaling inArabidopsis   

Abstract

Plants have evolved sophisticated mechanisms for integration of endogenous and exogenous signals to adapt to the changing environment. Both the phytohormones jasmonate (JA) and ethylene (ET) regulate plant growth, development, and defense. In addition to synergistic regulation of root hair development and resistance to necrotrophic fungi, JA and ET act antagonistically to regulate gene expression, apical hook curvature, and plant defense against insect attack. However, the molecular mechanism for such antagonism between JA and ET signaling remains unclear. Here, we demonstrate that interaction between the JA-activated transcription factor MYC2 and the ET-stabilized transcription factor ETHYLENE-INSENSITIVE3 (EIN3) modulates JA and ET signaling antagonism in Arabidopsis thaliana. MYC2 interacts with EIN3 to attenuate the transcriptional activity of EIN3 and repress ET-enhanced apical hook curvature. Conversely, EIN3 interacts with and represses MYC2 to inhibit JA-induced expression of wound-responsive genes and herbivory-inducible genes and to attenuate JA-regulated plant defense against generalist herbivores. Coordinated regulation of plant responses in both antagonistic and synergistic manners would help plants adapt to fluctuating environments.

Arabidopsis MYC Transcription Factors Are the Target of Hormonal Salicylic Acid/Jasmonic Acid Cross Talk in Response to Pieris brassicae Egg Extract

“…For example, ET perception negatively affected expression of wound-regulated genes (Rojo et al, 1999), and ein2-1 plants were more resistant to herbivory (Bodenhausen and Reymond, 2007). At the molecular level, EIN3 and EIL, which are key transcription factors of the ET pathway, interacted with and repressed MYC2 transcriptional activity (Song et al, 2014). Here, we show that PDF1.2 expression was induced by egg extract treatment and that this induction was abolished in npr1-1 ein2-1, suggesting that the ET pathway is activated by insect eggs.…”

The Mechanistic Underpinnings of an ago1-Mediated, Environmentally Dependent, and Stochastic Phenotype

“…ET and JA synergistically promote defense against necrotrophic fungal pathogens through ethylene-responsive transcription factors (ERFs; Lorenzo et al, 2003). However, ET represses JA-dependent herbivory responses (Ballaré, 2011) by antagonizing the transcription factor MYC2 (Anderson et al, 2004;Lorenzo et al, 2004;Song et al, 2014).Here, we provide evidence that AGO1 maintains phenotypic robustness in the face of an environmental challenge and integrates environmental signals through these canonical defense pathways. We show that ago1 mutant plants develop lesions on embryonic leaves (cotyledons) when grown under full-spectrum light conditions.…”

“…ET and JA synergistically promote defense against necrotrophic fungal pathogens through ethylene-responsive transcription factors (ERFs; Lorenzo et al, 2003). However, ET represses JA-dependent herbivory responses (Ballaré, 2011) by antagonizing the transcription factor MYC2 (Anderson et al, 2004;Lorenzo et al, 2004;Song et al, 2014).…”

Type-B ARABIDOPSIS RESPONSE REGULATORs Specify the Shoot Stem Cell Niche by Dual Regulation of WUSCHEL

“…The pGreenII 0800-LUC vector harboring the renilla luciferase (REN) gene under the control of the Pro35S promoter was used as the internal control. Protoplast transient expression assays were performed as previously described (Song et al, 2014). Mesophyll protoplast preparation and transfection were performed according to a previously reported method (Yoo et al, 2007).…”