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Transcriptomics in Erigeron canadensis reveals rapid photosynthetic and hormonal responses to auxin herbicide application

The perception pathway for endogenous auxin has been well described, yet the mode of action of synthetic auxin herbicides, used for >70 years, remains uncharacterized. We utilized transcriptomics and targeted physiological studies to investigate the unknown rapid response to synthetic auxin herbi...

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Autores principales: McCauley, Cara L, McAdam, Scott A M, Bhide, Ketaki, Thimmapuram, Jyothi, Banks, Jo Ann, Young, Bryan G
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7307852/
https://www.ncbi.nlm.nih.gov/pubmed/32161961
http://dx.doi.org/10.1093/jxb/eraa124
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author McCauley, Cara L
McAdam, Scott A M
Bhide, Ketaki
Thimmapuram, Jyothi
Banks, Jo Ann
Young, Bryan G
author_facet McCauley, Cara L
McAdam, Scott A M
Bhide, Ketaki
Thimmapuram, Jyothi
Banks, Jo Ann
Young, Bryan G
author_sort McCauley, Cara L
collection PubMed
description The perception pathway for endogenous auxin has been well described, yet the mode of action of synthetic auxin herbicides, used for >70 years, remains uncharacterized. We utilized transcriptomics and targeted physiological studies to investigate the unknown rapid response to synthetic auxin herbicides in the globally problematic weed species Erigeron canadensis. Synthetic auxin herbicide application consistently and rapidly down-regulated the photosynthetic machinery. At the same time, there was considerable perturbation to the expression of many genes related to phytohormone metabolism and perception. In particular, auxin herbicide application enhanced the expression of the key abscisic acid biosynthetic gene, 9-cis-epoxycarotenoid deoxygenase (NCED). The increase in NCED expression following auxin herbicide application led to a rapid biosynthesis of abscisic acid (ABA). This increase in ABA levels was independent of a loss of cell turgor or an increase in ethylene levels, both proposed triggers for rapid ABA biosynthesis. The levels of ABA in the leaf after auxin herbicide application continued to increase as plants approached death, up to >3-fold higher than in the leaves of plants that were drought stressed. We propose a new model in which synthetic auxin herbicides trigger plant death by the whole-scale, rapid, down-regulation of photosynthetic processes and an increase in ABA levels through up-regulation of NCED expression, independent of ethylene levels or a loss of cell turgor.
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spelling pubmed-73078522020-06-29 Transcriptomics in Erigeron canadensis reveals rapid photosynthetic and hormonal responses to auxin herbicide application McCauley, Cara L McAdam, Scott A M Bhide, Ketaki Thimmapuram, Jyothi Banks, Jo Ann Young, Bryan G J Exp Bot Research Papers The perception pathway for endogenous auxin has been well described, yet the mode of action of synthetic auxin herbicides, used for >70 years, remains uncharacterized. We utilized transcriptomics and targeted physiological studies to investigate the unknown rapid response to synthetic auxin herbicides in the globally problematic weed species Erigeron canadensis. Synthetic auxin herbicide application consistently and rapidly down-regulated the photosynthetic machinery. At the same time, there was considerable perturbation to the expression of many genes related to phytohormone metabolism and perception. In particular, auxin herbicide application enhanced the expression of the key abscisic acid biosynthetic gene, 9-cis-epoxycarotenoid deoxygenase (NCED). The increase in NCED expression following auxin herbicide application led to a rapid biosynthesis of abscisic acid (ABA). This increase in ABA levels was independent of a loss of cell turgor or an increase in ethylene levels, both proposed triggers for rapid ABA biosynthesis. The levels of ABA in the leaf after auxin herbicide application continued to increase as plants approached death, up to >3-fold higher than in the leaves of plants that were drought stressed. We propose a new model in which synthetic auxin herbicides trigger plant death by the whole-scale, rapid, down-regulation of photosynthetic processes and an increase in ABA levels through up-regulation of NCED expression, independent of ethylene levels or a loss of cell turgor. Oxford University Press 2020-06-22 2020-03-12 /pmc/articles/PMC7307852/ /pubmed/32161961 http://dx.doi.org/10.1093/jxb/eraa124 Text en © The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Experimental Biology. http://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Papers
McCauley, Cara L
McAdam, Scott A M
Bhide, Ketaki
Thimmapuram, Jyothi
Banks, Jo Ann
Young, Bryan G
Transcriptomics in Erigeron canadensis reveals rapid photosynthetic and hormonal responses to auxin herbicide application
title Transcriptomics in Erigeron canadensis reveals rapid photosynthetic and hormonal responses to auxin herbicide application
title_full Transcriptomics in Erigeron canadensis reveals rapid photosynthetic and hormonal responses to auxin herbicide application
title_fullStr Transcriptomics in Erigeron canadensis reveals rapid photosynthetic and hormonal responses to auxin herbicide application
title_full_unstemmed Transcriptomics in Erigeron canadensis reveals rapid photosynthetic and hormonal responses to auxin herbicide application
title_short Transcriptomics in Erigeron canadensis reveals rapid photosynthetic and hormonal responses to auxin herbicide application
title_sort transcriptomics in erigeron canadensis reveals rapid photosynthetic and hormonal responses to auxin herbicide application
topic Research Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7307852/
https://www.ncbi.nlm.nih.gov/pubmed/32161961
http://dx.doi.org/10.1093/jxb/eraa124
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