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Front. Plant Sci. | doi: 10.3389/fpls.2018.01675

AP2/ERF Family Transcription Factors ORA59 and RAP2.3 Interact in the Nucleus and Function Together in Ethylene Responses

 Na Young Kim1, Young Jin Jang1 and  Ohkmae K. Park1*
  • 1Korea University, South Korea

The gaseous plant hormone ethylene is a key signaling molecule regulating plant growth, development, and defense against pathogens. OCTADECANOID-RESPONSIVE ARABIDOPSIS 59 (ORA59) is an ETHYLENE RESPONSE FACTOR (ERF) transcription factor and has been suggested to integrate ethylene and jasmonic acid signaling and regulate resistance to necrotrophic pathogens. Here we screened for ORA59 interactors using the yeast two-hybrid system to elucidate the molecular function of ORA59. This led to the identification of RELATED TO AP2.3 (RAP2.3), another ERF transcription factor belonging to the group VII ERF family. In binding assays, ORA59 and RAP2.3 interacted in the nucleus and showed ethylene-dependent nuclear localization. ORA59 played a positive role in ethylene-regulated responses, including the triple response, featured by short, thick hypocotyl and root, and exaggerated apical hook in dark-grown seedlings, and resistance to the necrotrophic pathogen Pectobacterium carotovorum, as shown by the increased and decreased ethylene sensitivity and disease resistance in ORA59-overexpressing (ORA59OE) and null mutant (ora59) plants, respectively. In genetic crosses, ORA59OE rap2.3 crossed lines lost ORA59-mediated positive effects and behaved like rap2.3 mutant. These results suggest that ORA59 physically interacts with RAP2.3 and that this interaction is important for the regulatory roles of ORA59 in ethylene responses.

Keywords: Arabidopsis thaliana, ORA59, RAP2.3, ethylene response factor, ethylene, Disease Resistance, Plant Immunity, Pectobacterium carotovorum

Received: 11 Sep 2018; Accepted: 26 Oct 2018.

Edited by:

Jens Staal, Ghent University, Belgium

Reviewed by:

Silvia Proietti, Università degli Studi della Tuscia, Italy
Jorge Vicente, University of Nottingham, United Kingdom  

Copyright: © 2018 Kim, Jang and Park. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Ohkmae K. Park, Korea University, Seoul, 136-701, South Korea, omkim@korea.ac.kr