Dynamic balancing of isoprene carbon sources reflects photosynthetic and photorespiratory responses to temperature stress

Jardine, Kolby, Chambers, Jeffrey, Alves, Eliane G., Teixeira, Andrea, Garcia, Sabrina, Holm, Jennifer, Higuchi, Niro, Manzi, Antonio, Abrell, Leif, Fuentes, Jose D., Nielsen, Lars K., Torn, Margaret S. and Vickers, Claudia E. (2014) Dynamic balancing of isoprene carbon sources reflects photosynthetic and photorespiratory responses to temperature stress. Plant Physiology, 166 4: 2051-2064. doi:10.1104/pp.114.247494


Author Jardine, Kolby
Chambers, Jeffrey
Alves, Eliane G.
Teixeira, Andrea
Garcia, Sabrina
Holm, Jennifer
Higuchi, Niro
Manzi, Antonio
Abrell, Leif
Fuentes, Jose D.
Nielsen, Lars K.
Torn, Margaret S.
Vickers, Claudia E.
Title Dynamic balancing of isoprene carbon sources reflects photosynthetic and photorespiratory responses to temperature stress
Journal name Plant Physiology   Check publisher's open access policy
ISSN 1532-2548
0032-0889
Publication date 2014-12-01
Year available 2014
Sub-type Article (original research)
DOI 10.1104/pp.114.247494
Open Access Status DOI
Volume 166
Issue 4
Start page 2051
End page 2064
Total pages 14
Place of publication Rockville, MD, United States
Publisher American Society of Plant Biologists
Language eng
Subject 1314 Physiology
1311 Genetics
1110 Plant Science
Abstract The volatile gas isoprene is emitted in teragrams per annum quantities from the terrestrial biosphere and exerts a large effect on atmospheric chemistry. Isoprene is made primarily from recently fixed photosynthate; however, alternate carbon sources play an important role, particularly when photosynthate is limiting. We examined the relative contribution of these alternate carbon sources under changes in light and temperature, the two environmental conditions that have the strongest influence over isoprene emission. Using a novel real-time analytical approach that allowed us to examine dynamic changes in carbon sources, we observed that relative contributions do not change as a function of light intensity. We found that the classical uncoupling of isoprene emission from net photosynthesis at elevated leaf temperatures is associated with an increased contribution of alternate carbon. We also observed a rapid compensatory response where alternate carbon sources compensated for transient decreases in recently fixed carbon during thermal ramping, thereby maintaining overall increases in isoprene production rates at high temperatures. Photorespiration is known to contribute to the decline in net photosynthesis at high leaf temperatures. A reduction in the temperature at which the contribution of alternate carbon sources increased was observed under photorespiratory conditions, while photosynthetic conditions increased this temperature. Feeding [2-C-13] glycine (a photorespiratory intermediate) stimulated emissions of [C-13(1-5)] isoprene and (CO2)-C-13, supporting the possibility that photorespiration can provide an alternate source of carbon for isoprene synthesis. Our observations have important implications for establishing improved mechanistic predictions of isoprene emissions and primary carbon metabolism, particularly under the predicted increases in future global temperatures.
Formatted abstract
The volatile gas isoprene is emitted in teragrams per annum quantities from the terrestrial biosphere and exerts a large effect on atmospheric chemistry. Isoprene is made primarily from recently fixed photosynthate; however, alternate carbon sources play an important role, particularly when photosynthate is limiting. We examined the relative contribution of these alternate carbon sources under changes in light and temperature, the two environmental conditions that have the strongest influence over isoprene emission. Using a novel real-time analytical approach that allowed us to examine dynamic changes in carbon sources, we observed that relative contributions do not change as a function of light intensity. We found that the classical uncoupling of isoprene emission from net photosynthesis at elevated leaf temperatures is associated with an increased contribution of alternate carbon. We also observed a rapid compensatory response where alternate carbon sources compensated for transient decreases in recently fixed carbon during thermal ramping, thereby maintaining overall increases in isoprene production rates at high temperatures. Photorespiration is known to contribute to the decline in net photosynthesis at high leaf temperatures. A reduction in the temperature at which the contribution of alternate carbon sources increased was observed under photorespiratory conditions, while photosynthetic conditions increased this temperature. Feeding [2-13C]glycine (a photorespiratory intermediate) stimulated emissions of [13C1–5]isoprene and 13CO2, supporting the possibility that photorespiration can provide an alternate source of carbon for isoprene synthesis. Our observations have important implications for establishing improved mechanistic predictions of isoprene emissions and primary carbon metabolism, particularly under the predicted increases in future global temperatures.
Keyword Temperature stress
Photosynthetic responses
Photorespiratory responses
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID DE-AC02-05CH11231
CHE0216226
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
Australian Institute for Bioengineering and Nanotechnology Publications
 
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