Dynamics of Metabolic Responses to Combined Heat and Drought Spells in Arabidopsis Thaliana under Ambient and Rising Atmospheric CO2 (original) (raw)
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Global Change Biology
Climate changes increasingly threaten plant growth and productivity. Such changes are complex and involve multiple environmental factors, including rising CO2 levels and climate extreme events. As the molecular and physiological mechanisms underlying plant responses to realistic future climate extreme conditions are still poorly understood, a multiple organizational level-analysis (i.e. eco-physiological, biochemical and transcriptional) was performed, using Arabidopsis exposed to incremental heat wave and water deficit under ambient and elevated CO2. The climate extreme resulted in biomass reduction, photosynthesis inhibition, and considerable increases in stress parameters. Photosynthesis was a major target as demonstrated at the physiological and transcriptional levels. In contrast, the climate extreme treatment induced a protective effect on oxidative membrane damage, most likely as a result of strongly increased lipophilic antioxidants and membrane-protecting enzymes. Elevated CO2 significantly mitigated the negative impact of a combined heat and drought, as apparent in biomass reduction, photosynthesis inhibition, chlorophyll fluorescence decline, H2O2 production and protein oxidation. Analysis of enzymatic and molecular antioxidants revealed that the stress-mitigating CO2 effect operates through up-regulation of antioxidant defense metabolism, as well as by reduced photorespiration resulting in lowered oxidative pressure. Therefore, exposure to future climate extreme episodes will negatively impact plant growth and production, but elevated CO2 is likely to mitigate this effect.
Frontiers in Plant Science
Future climate change is set to have an impact on the physiological performance of global vegetation. Increasing temperature and atmospheric CO 2 concentration will affect plant growth, net primary productivity, photosynthetic capability, and other biochemical functions that are essential for normal metabolic function. Alongside the primary metabolic function effects of plant growth and development, the effect of stress on plant secondary metabolism from both biotic and abiotic sources will be impacted by changes in future climate. Using an untargeted metabolomic fingerprinting approach alongside emissions measurements, we investigate for the first time how elevated atmospheric CO 2 and temperature both independently and interactively impact on plant secondary metabolism through resource allocation, with a resulting "trade-off" between secondary metabolic processes in Salix spp. and in particular, isoprene biosynthesis. Although it has been previously reported that isoprene is suppressed in times of elevated CO 2 , and that isoprene emissions increase as a response to short-term heat shock, no study has investigated the interactive effects at the metabolic level. We have demonstrated that at a metabolic level isoprene is still being produced during periods of both elevated CO 2 and temperature, and that ultimately temperature has the greater effect. With global temperature and atmospheric CO 2 concentrations rising as a result of anthropogenic activity, it is imperative to understand the interactions between atmospheric processes and global vegetation, especially given that global isoprene emissions have the potential to contribute to atmospheric warming mitigation.
Plant responses to climate change: metabolic changes under combined abiotic stresses
Journal of Experimental Botany, 2022
Climate change is predicted to increase the frequency and intensity of abiotic stress combinations that negatively impact plants and pose a serious threat to crop yield and food supply. Plants respond to episodes of stress combination by activating specific physiological and molecular responses, as well as by adjusting different metabolic pathways, to mitigate the negative effects of the stress combination on plant growth, development, and reproduction. Plants synthesize a wide range of metabolites that regulate many aspects of plant growth and development, as well as plant responses to stress. Although metabolic responses to individual abiotic stresses have been studied extensively in different plant species, recent efforts have been directed at understanding metabolic responses that occur when different abiotic factors are combined. In this review we examine recent studies of metabolomic changes under stress combination in different plants and suggest new avenues for the developme...
Constraint-based approaches have been used for integrating data in large-scale metabolic networks to obtain insights into metabolism of various organisms. Due to the underlying steady-state assumption, these approaches are usually not suited for making predictions about metabolite levels. Here, we ask whether we can make inferences about the variability of metabolite levels from a constraint-based analysis based on the integration of transcriptomics data. To this end, we analyze time-resolved transcriptomics and metabolomics data from Arabidopsis thaliana under a set of eight different light and temperature conditions. In a previous study, the gene expression data have already been integrated in a genome-scale metabolic network to predict pathways, termed modulators and sustainers, which are differentially regulated with respect to a biochemically meaningful data-driven null model. Here, we present a follow-up analysis which bridges the gap between flux- and metabolite-centric methods. One of our main findings demonstrates that under certain environmental conditions, the levels of metabolites acting as substrates in modulators or sustainers show significantly lower temporal variations with respect to the remaining measured metabolites. This observation is discussed within the context of a systems-view of plasticity and robustness of metabolite contents and pathway fluxes. Our study paves the way for investigating the existence of similar principles in other species for which both genome-scale networks and high-throughput metabolomics data of high quality are becoming increasingly available.
Exploring the Temperature-Stress Metabolome of Arabidopsis
Plant Physiology, 2004
Metabolic profiling analyses were performed to determine metabolite temporal dynamics associated with the induction of acquired thermotolerance in response to heat shock and acquired freezing tolerance in response to cold shock. Low-M r polar metabolite analyses were performed using gas chromatography-mass spectrometry. Eighty-one identified metabolites and 416 unidentified mass spectral tags, characterized by retention time indices and specific mass fragments, were monitored. Cold shock influenced metabolism far more profoundly than heat shock. The steady-state pool sizes of 143 and 311 metabolites or mass spectral tags were altered in response to heat and cold shock, respectively. Comparison of heat-and cold-shock response patterns revealed that the majority of heat-shock responses were shared with cold-shock responses, a previously unknown relationship. Coordinate increases in the pool sizes of amino acids derived from pyruvate and oxaloacetate, polyamine precursors, and compatible solutes were observed during both heat and cold shock. In addition, many of the metabolites that showed increases in response to both heat and cold shock in this study were previously unlinked with temperature stress. This investigation provides new insight into the mechanisms of plant adaptation to thermal stress at the metabolite level, reveals relationships between heat-and cold-shock responses, and highlights the roles of known signaling molecules and protectants. ; fax 352-392-1413.
(138) Metabolite Profiling in Heat- and Drought-stressed Arabidopsis
HortScience
Drought and heat stress have been extensively studied in plants, but little is known about how the combination of drought and heat impact their physiology and metabolism. The metabolite profile of Arabidopsis subjected to heat, drought, and the combination of heat and drought were analyzed by gas-chromatography-mass spectrometry (GC-MS). Fatty acid retention time standards and the internal standard (IS) ribitol (adonitol) were added to each leaf sample and the polar phase was extracted, methoximated, and derivatized (trimethylsilylated) prior to analysis by GC-MS (Trace DSQ with Combi-PAL autosampler). Compounds were identified based upon retention time (relative to fatty acid standards) and comparison with reference spectra in our custom mass spectral library. Semi-quantitation of compound peak area was done relative to the internal standard. Plants subjected to both heat and drought stress accumulated sucrose and other sugars/sugar alchohols such as maltose, gulose, mannitol. The ...
Data in Brief, 2020
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PLoS ONE, 2012
Background: In tightly closed human habitats such as space stations, locations near volcano vents and closed culture vessels, atmospheric CO 2 concentration may be 10 to 20 times greater than Earth's current ambient levels. It is known that super-elevated (SE) CO 2 (.1,200 mmol mol 21) induces physiological responses different from that of moderately elevated CO 2 (up to 1,200 mmol mol 21), but little is known about the molecular responses of plants to supra-optimal [CO 2 ]. Methodology/Principal Findings: To understand the underlying molecular causes for differential physiological responses, metabolite and transcript profiles were analyzed in aerial tissue of Arabidopsis plants, which were grown under ambient atmospheric CO 2 (400 mmol mol 21), elevated CO 2 (1,200 mmol mol 21) and SE CO 2 (4,000 mmol mol 21), at two developmental stages early and late vegetative stage. Transcript and metabolite profiling revealed very different responses to elevated versus SE [CO 2 ]. The transcript profiles of SE CO 2 treated plants were closer to that of the control. Development stage had a clear effect on plant molecular response to elevated and SE [CO 2 ]. Photosynthetic acclimation in terms of downregulation of photosynthetic gene expression was observed in response to elevated [CO 2 ], but not that of SE [CO 2 ] providing the first molecular evidence that there appears to be a fundamental disparity in the way plants respond to elevated and SE [CO 2 ]. Although starch accumulation was induced by both elevated and SE [CO 2 ], the increase was less at the late vegetative stage and accompanied by higher soluble sugar content suggesting an increased starch breakdown to meet sink strength resulting from the rapid growth demand. Furthermore, many of the elevated and SE CO 2-responsive genes found in the present study are also regulated by plant hormone and stress. Conclusions/Significance: This study provides new insights into plant acclimation to elevated and SE [CO 2 ] during development and how this relates to stress, sugar and hormone signaling.