Exploring the Temperature-Stress Metabolome of Arabidopsis

Abstract

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.Environmental stresses arise from conditions that are unfavorable for the optimal growth and development of organisms (Levitt, 1972;Guy, 1999). Environmental stresses can be classified either as abiotic or biotic. Abiotic stresses are produced by inappropriate levels of physical components of the environment, including temperature extremes. Biotic stresses are caused by pathogens, parasites, predators, and other competing organisms. Even though biotic and abiotic stresses cause injury through unique mechanisms that result in specific responses, all forms of stress seem to elicit a common set of responses (Levitt, 1972). For instance, both biotic and abiotic stresses can result in oxidative stress through the formation of free radicals, which are highly destructive to lipids, nucleic acids, and proteins (Mittler, 2002). Another example is water stress, which is produced as a secondary stress by chilling, freezing, heat, and salt, as a tertiary stress by radiation, and, of course, as a primary stress during drought (Levitt, 1972).The ability of most organisms to survive and recover from unfavorable conditions is a function of basal and acquired tolerance mechanisms. Acquired tolerance involves a set of mechanisms that can transiently extend or improve overall stress tolerance (Levitt, 1972;Hallberg et al., 1985;Guy, 1999;Thomashow, 1999) following exposure to moderate stress conditions. For example, if plants are preexposed to a nonlethal high temperature, they can acquire enhanced tolerance to otherwise lethal high temperatures. Similarly, many plants can tolerate a gre...

Comprehensive Dissection of Spatiotemporal Metabolic Shifts in Primary, Secondary, and Lipid Metabolism during Developmental Senescence in Arabidopsis

“…5B). Increases of both metabolites as osmoprotectants under stress conditions such as cold, heat, salt, and drought have been well documented (Taji et al, 2002;Kaplan et al, 2004Kaplan et al, , 2007Nishizawa et al, 2008;Sanchez et al, 2008). The high accumulation of these metabolites might be needed to protect the plant cells in the basal region to allow the progression of senescence, presumably to sustain functionality (e.g.…”

A Key Role for Apoplastic H2O2 in Norway Spruce Phenolic Metabolism

“…Extraction, GC-MS profiling, and the subsequent processing of GC-MS data were conducted as described previously (Kaplan et al, 2004;Damiani et al, 2005;Desbrosses et al, 2005;Dauwe et al, 2007) using an HP6890 series mass spectrometry system coupled to a 5973 mass selective detector (Agilent Technologies). The identification of primary metabolites was based on the quadrupole mass spectral and retention time index library (i.e.…”

Effects of facultative symbionts and heat stress on the metabolome of pea aphids

“…b-Alanine production is a conserved response to heat stress in organisms as distantly related as Drosophila and Arabidopsis, and b-alanine may be a chemical chaperone, preserving enzyme function during heat-shock (Kaplan et al, 2004;Mehta and Seidler, 2005;Malmendal et al, 2006). Polyamine production is another conserved response to heat in animals and plants, and, although increases were not observed in heat-shocked aphids, polyamine precursors arginine and ornithine decreased and byproduct 5 0 -deoxy-5 0 -methylthioadenosine increased after heat-shock, suggesting that polyamine biosynthesis occurred (Michaud et al, 2008).…”