Constitutively Elevated Salicylic Acid Levels Alter Photosynthesis and Oxidative State but Not Growth in Transgenic Populus
Salicylic acid (SA) has long been implicated in plant responses to oxidative stress. SA overproduction in Arabidopsis thaliana leads to dwarfism, making in planta assessment of SA effects difficult in this model system. We report that transgenic Populus tremula × alba expressing a bacterial SA synth...
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Published in | The Plant cell Vol. 25; no. 7; pp. 2714 - 2730 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
American Society of Plant Biologists
01.07.2013
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Subjects | |
Online Access | Get full text |
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Summary: | Salicylic acid (SA) has long been implicated in plant responses to oxidative stress. SA overproduction in Arabidopsis thaliana leads to dwarfism, making in planta assessment of SA effects difficult in this model system. We report that transgenic Populus tremula × alba expressing a bacterial SA synthase hyperaccumulated SA and SA conjugates without negative growth consequences. In the absence of stress, endogenously elevated SA elicited widespread metabolic and transcriptional changes that resembled those of wild-type plants exposed to oxidative stress-promoting heat treatments. Potential signaling and oxidative stress markers azelaic and gluconic acids as well as antioxidant chlorogenic acids were strongly coregulated with SA, while soluble sugars and other phenylpropanoids were inversely correlated. Photosynthetic responses to heat were attenuated in SA-overproducing plants. Network analysis identified potential drivers of SA-mediated transcriptome rewiring, including receptor-like kinases and WRKY transcription factors. Orthologs of Arabidopsis SA signaling components NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES1 and thioredoxins were not represented. However, all members of the expanded Populus nucleoredoxin-1 family exhibited increased expression and increased network connectivity in SA-overproducing Populus, suggesting a previously undescribed role in SA-mediated redox regulation. The SA response in Populus involved a reprogramming of carbon uptake and partitioning during stress that is compatible with constitutive chemical defense and sustained growth, contrasting with the SA response in Arabidopsis, which is transient and compromises growth if sustained. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Some figures in this article are displayed in color online but in black and white in the print edition. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantcell.org) is: Chung-Jui Tsai (cjtsai@uga.edu). www.plantcell.org/cgi/doi/10.1105/tpc.113.112839 Current address: Guangdong Academy of Forestry, Guangzhou, 510520 China. Online version contains Web-only data. Current address: Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973. Current address: Medical Imaging Consultants, Gainesville, FL 32606. Current address: University of Eldoret, Eldoret, 30100, Kenya. |
ISSN: | 1040-4651 1532-298X |
DOI: | 10.1105/tpc.113.112839 |