Light modulates ethylene synthesis, signaling, and downstream transcriptional networks to control plant development
- 1Department of Biology and Center for Molecular Signaling, Wake Forest University, United States
- 2Department of Botany and Plant Pathology, Purdue University, United States
- 3Dept of Molecular Biology, Cell Biology & Biochemistry, Brown University, United States
The inhibition of hypocotyl elongation by ethylene in dark-grown seedlings was the basis of elegant screens that identified ethylene-insensitive Arabidopsis mutants, which remained tall even when treated with high concentrations of ethylene. This simple approach proved invaluable for identification and molecular characterization of major players in the ethylene signaling and response pathway, including receptors and downstream signaling proteins, as well as transcription factors that mediate the extensive transcriptional remodeling observed in response to elevated ethylene. However, the dark-adapted early developmental stage used in these experiments represents only a small segment of a plant’s life cycle. After a seedling’s emergence from the soil, light signaling pathways elicit a switch in developmental programming and the hormonal circuitry that controls it. Accordingly, ethylene levels and responses diverge under these different environmental conditions. In this review, we compare and contrast ethylene synthesis, perception, and response in light and dark contexts, including the molecular mechanisms linking light responses to ethylene biology. One powerful method to identify similarities and differences in these important regulatory processes is through comparison of transcriptomic datasets resulting from manipulation of ethylene levels or signaling under varying light conditions. We performed a meta-analysis of multiple transcriptomic datasets to uncover transcriptional responses to ethylene that are both light-dependent and light-independent. We identified a core set of 139 transcripts with robust and consistent responses to elevated ethylene across three root-specific datasets. This “gold standard” group of ethylene-regulated transcripts includes mRNAs encoding numerous proteins that function in ethylene signaling and synthesis, but also reveals a number of previously uncharacterized gene products that may contribute to ethylene response phenotypes. Understanding these light-dependent differences in ethylene signaling and synthesis will provide greater insight into the roles of ethylene in growth and development across the entire plant life cycle.
Keywords: Light, ethylene biosynthesis, Hypocotyl, root, Transcriptome, ACC (1-aminocyclopropane-1-carboxylic acid), transcriptional meta-analysis, ethylene signaling, ethylene
Received: 02 Jun 2019;
Accepted: 09 Aug 2019.
Edited by:Dominique Van Der Straeten, Ghent University, Belgium
Reviewed by:Jan Smalle, University of Kentucky, United States
Anna N. Stepanova, North Carolina State University, United States
Copyright: © 2019 Harkey, Yoon, Seo, DeLong and Muday. 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: Dr. Gloria Muday, Wake Forest University, Department of Biology and Center for Molecular Signaling, Winston-Salem, 27106, North Carolina, United States, email@example.com