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Temporal and spatial transcriptomic and microRNA dynamics of CAM photosynthesis in pineapple
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Ching M. Wai Robert VanBuren Jisen Zhang Lixian Huang Wenjing Miao Patrick P. Edger Won C. Yim Henry D. Priest Blake C. Meyers Todd Mockler J. Andrew C. Smith John C. Cushman Ray Ming 《The Plant journal : for cell and molecular biology》2017,92(1):19-30
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The circadian clock is considered a central “orchestrator” of gene expression and metabolism. Concomitantly, the circadian clock is considered of negligible influence in the field and beyond leaf levels, where direct physiological responses to environmental cues are considered the main drivers of diel fluctuations. I propose to bridge the gap across scales by examining current evidence on whether circadian rhythmicity in gas exchange is relevant for field settings and at the ecosystem scale. Nocturnal stomatal conductance and water fluxes appear to be influenced by a “hard” clock that may override the direct physiological responses to the environment. Tests on potential clock controls over photosynthetic carbon assimilation and daytime transpiration are scant yet, if present, could have a large impact on our current understanding and modeling of the exchanges of carbon dioxide and water between terrestrial ecosystems and the atmosphere. 相似文献
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Induction of Crassulacean acid metabolism by water limitation 总被引:5,自引:0,他引:5
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SUMMARY: The photosynthetic specialization of crassulacean acid metabolism (CAM) has evolved many times in response to selective pressures imposed by water limitation. Integration of circadian and metabolite control over nocturnal C? and daytime C? carboxylation processes in CAM plants provides plasticity for optimizing carbon gain and water use by extending or curtailing the period of net CO? uptake over any 24-h period. Photosynthetic plasticity underpins the ecological diversity of CAM species and contributes to the potential for high biomass production in water-limited habitats. Perceived evolutionary constraints on the dynamic range of CO? acquisition strategies in CAM species can be reconciled with functional anatomical requirements and the metabolic costs of maintaining the enzymatic machinery required for C? and C? carboxylation processes. Succulence is highlighted as a key trait for maximizing biomass productivity in water-limited habitats by serving to buffer water availability, by maximizing the magnitude of nocturnal CO? uptake and by extending the duration of C? carboxylation beyond the night period. Examples are discussed where an understanding of the diverse metabolic and ecological manifestations of CAM can be exploited for the sustainable productivity of economically and ecologically important species. 相似文献
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Stimulation or light-saturated rates of photosynthesis in Ectocarpus siliculosus (Dillwyn) Lyngb. by blue light was eliminated by increasing dissolved inorganic carbon (DIC) or by lowering pH in natural seawater. The amplitude of the circadian rhythm of photosynthesis was also diminished under these conditions, and the pH compensation points in a closed system were higher in the presence of blue light and during the circadian day. These observations suggest that blue light and the circadian clock regulate the activity of a carbon acquisition system in these plants. The inhibitor of external carbonic anhydrase, acetazolamide, reduced overall rates of photosynthesis by only about 30%, but ethoxyzolamide suppressed the circadian rhythm of photosynthesis almost completely and markedly reduced the duration of responses to blue light pulses. Similar patterns were obtained when photosynthesis was measured in strongly limiting DIC concentrations (0–0.5 mol m?3). Since blue light stimulated photosynthesis under these conditions of strong carbon limitation, we suggest that blue light activates the release of CO2 from an internal CO2 store. We propose a metabolic pathway with similarities to that of CAM plants. Non-photosynthetic fixation leads to the accumulation of a storage metabolite. The circadian clock and blue light control the mobilization of CO2 at the site of decarboxylation of this metabolite. In the presence of continuous blue light the pathway is proposed to cycle and act as a pump for CO2 into the chloroplasts. This hypothesis helps to explain a number of previously reported peculiarities of brown algal photosynthesis. 相似文献
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Ruts T Matsubara S Wiese-Klinkenberg A Walter A 《Journal of experimental botany》2012,63(9):3339-3351
Plants are sessile organisms forced to adjust to their surrounding environment. In a single plant the photoautotrophic shoot is exposed to pronounced environmental variations recurring in a day-night 24?h (diel) cycle, whereas the heterotrophic root grows in a temporally less fluctuating environment. The contrasting habitats of shoots and roots are reflected in different diel growth patterns and their responsiveness to environmental stimuli. Differences between diel leaf growth patterns of mono- and dicotyledonous plants correspond to their different organization and placement of growth zones. In monocots, heterotrophic growth zones are organized linearly and protected from the environment by sheaths of older leaves. In contrast, photosynthetically active growth zones of dicot leaves are exposed directly to the environment and show characteristic, species-specific diel growth patterns. It is hypothesized that the different exposure to environmental constraints and simultaneously the sink/source status of the growing organs may have induced distinct endogenous control of diel growth patterns in roots and leaves of monocot and dicot plants. Confronted by strong temporal fluctuations in environment, the circadian clock may facilitate robust intrinsic control of leaf growth in dicot plants. 相似文献
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CAM photosynthesis in submerged aquatic plants 总被引:1,自引:0,他引:1
Jon E. Keeley 《The Botanical review》1998,64(2):121-175
Crassulacean acid metabolism (CAM) is a CO2-concentrating mechanism selected in response to aridity in terrestrial habitats, and, in aquatic environments, to ambient limitations of carbon. Evidence is reviewed for its presence in five genera of aquatic vascular plants, includingIsoëtes, Sagittaria, Vallisneria, Crassula, andLittorella. Initially, aquatic CAM was considered by some to be an oxymoron, but some aquatic species have been studied in sufficient detail to say definitively that they possess CAM photosynthesis. CO2-concentrating mechanisms in photosynthetic organs require a barrier to leakage; e.g., terrestrial C4 plants have suberized bundle sheath cells and terrestrial CAM plants high stomatal resistance. In aquatic CAM plants the primary barrier to CO2 leakage is the extremely high difrusional resistance of water. This, coupled with the sink provided by extensive intercellular gas space, generates daytime CO2(pi) comparable to terrestrial CAM plants. CAM contributes to the carbon budget by both net carbon gain and carbon recycling, and the magnitude of each is environmentally influenced. Aquatic CAM plants inhabit sites where photosynthesis is potentially limited by carbon. Many occupy moderately fertile shallow temporary pools that experience extreme diel fluctuations in carbon availability. CAM plants are able to take advantage of elevated nighttime CO2 levels in these habitats. This gives them a competitive advantage over non-CAM species that are carbon starved during the day and an advantage over species that expend energy in membrane transport of bicarbonate. Some aquatic CAM plants are distributed in highly infertile lakes, where extreme carbon limitation and light are important selective factors. Compilation of reports on diel changes in titratable acidity and malate show 69 out of 180 species have significant overnight accumulation, although evidence is presented discounting CAM in some. It is concluded that similar proportions of the aquatic and terrestrial floras have evolved CAM photosynthesis. AquaticIsoëtes (Lycophyta) represent the oldest lineage of CAM plants and cladistic analysis supports an origin for CAM in seasonal wetlands, from which it has radiated into oligotrophic lakes and into terrestrial habitats. Temperate Zone terrestrial species share many characteristics with amphibious ancestors, which in their temporary terrestrial stage, produce functional stomata and switch from CAM to C3. Many lacustrineIsoëtes have retained the phenotypic plasticity of amphibious species and can adapt to an aerial environment by development of stomata and switching to C3. However, in some neotropical alpine species, adaptations to the lacustrine environment are genetically fixed and these constitutive species fail to produce stomata or loose CAM when artificially maintained in an aerial environment. It is hypothesized that neotropical lacustrine species may be more ancient in origin and have given rise to terrestrial species, which have retained most of the characteristics of their aquatic ancestry, including astomatous leaves, CAM and sediment-based carbon nutrition. 相似文献
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Natural light cycles synchronize behavioral and physiological cycles over varying time periods in both plants and animals. Many scleractinian corals exhibit diel cycles of polyp expansion and contraction entrained by diel sunlight patterns, and monthly cycles of spawning or planulation that correspond to lunar moonlight cycles. The molecular mechanisms for regulating such cycles are poorly understood. In this study, we identified four molecular clock genes (cry1, cry2, clock and cycle) in the scleractinian coral, Favia fragum, and investigated patterns of gene expression hypothesized to be involved in the corals' diel polyp behavior and lunar reproductive cycles. Using quantitative PCR, we measured fluctuations in expression of these clock genes over both diel and monthly spawning timeframes. Additionally, we assayed gene expression and polyp expansion-contraction behavior in experimental corals in normal light:dark (control) or constant dark treatments. Well-defined and reproducible diel patterns in cry1, cry2, and clock expression were observed in both field-collected and the experimental colonies maintained under control light:dark conditions, but no pattern was observed for cycle. Colonies in the control light:dark treatment also displayed diel rhythms of tentacle expansion and contraction. Experimental colonies in the constant dark treatment lost diel patterns in cry1, cry2, and clock expression and displayed a diminished and less synchronous pattern of tentacle expansion and contraction. We observed no pattern in cry1, cry2, clock, or cycle expression correlated with monthly spawning events suggesting these genes are not involved in the entrainment of reproductive cycles to lunar light cycles in F. fragum. Our results suggest a molecular clock mechanism, potentially similar to that in described in fruit flies, exists within F. fragum. 相似文献
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Previously, the authors have reported that intracellular amounts of several metabolic-related enzymes from the photosynthetic dinoflagellate Lingulodinium polyedrum(formerly Gonyaulax polyedra) showed a daily rhythm under a 12:12 h LD cycle. This led the authors to hypothesize that a circadian clock controls metabolism, including the tricarboxylic acid (TCA) cycle. In this study, the authors investigated daily changes in the levels of mRNA, protein, and enzyme activity of several metabolic enzymes during 12:12 h LD, 8:16 h LD, and constant light conditions. The NADP-dependent isocitrate dehydrogenase (NADPICDH) in the TCA cycle exhibited circadian changes of protein abundance and enzyme activity under all conditions, whereas its mRNA level remained constant throughout the cycle. These results indicate that the rhythm of NADPICDH is regulated by a circadian control of protein synthesis or modification rather than by message levels and suggest that the TCA cycle may be controlled by the circadian clock system. 相似文献
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Crassulacean acid metabolism (CAM) is recognized as a photosynthetic adaptation of plants to arid habitats. This paper presents a proof-of-concept evaluation of partitioning net CO2 exchanges for soil and plants in an arid, exclusively CAM mesocosm, with soil depth and succulent plant biomass approximating that of natural Sonoran Desert ecosystems. We present the first evidence that an enclosed CAM-dominated soil and plant community exposed to a substantial day/night temperature difference (30/20 degrees C), exhibits a diel gas exchange pattern consisting of four consecutive phases with a distinct nocturnal CO2 uptake. These phases were modulated by plant assimilation and soil respiration processes. Day-time stomatal closure of the CAM cycle during phase III was used to eliminate aboveground photosynthetic assimilation and respiration and thereby to estimate belowground plant plus soil respiration. Rapid changes in temperature appeared to synchronize single plant gas exchange but individual plant gas exchange patterns were desynchronized at constant day/night temperatures (25 degrees C), masking the distinct mesocosm pattern. Overall, the mean carbon budget of this CAM model Sonoran Desert system was negative, releasing an average of 22.5 mmol CO2 m-2 d-1. The capacity for nocturnal CO2 assimilation in this exclusively CAM mesocosm was inadequate to recycle CO2 released by plant and soil respiration. 相似文献
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Lüttge U 《Journal of experimental botany》2008,59(7):1503-1514
Clusia is the only genus with bona fide dicotyledonous trees performing Crassulacean acid metabolism (CAM). Clusia minor L. is extraordinarily flexible, being C(3)/CAM intermediate and expressing the photosynthetic modes C(3), CAM, CAM-cycling, and CAM-idling. C(3) photosynthesis and CAM can be observed simultaneously in two opposite leaves on a node and possibly even within the same leaf in the interveinal lamina and the major vein tissue, respectively. The relative activity of photosystem II (PhiPSII) indicating photosynthetic energy use, is larger under photorespiratory than under non-photorespiratory conditions due to the particular energy demand of photorespiration. The heterogeneity of PhiPSII over the leaves as visualized by chlorophyll fluorescence imaging in the C(3) mode is larger under non-photorespiratory conditions than under photorespiratory conditions. These observations indicate that photorespiration, presumably by its particular energy demand, synchronizes photosynthetic activity over the leaves. In the CAM mode, the heterogeneity of PhiPSII is more dependent on the transitions between CAM phases. Free-running circadian oscillations of photosynthesis are strongly dampened in both the C(3) and the CAM mode. Photorespiration is under circadian clock control in both the C(3) and the CAM mode. PhiPSII and the heterogeneity of PhiPSII oscillate in phase with CO(2) uptake and photorespiration only under non-photorespiratory conditions. Under photorespiratory conditions, PhiPSII does not oscillate and there is no heterogeneity, again indicating the stabilizing function of photorespiration. Plants acclimatized to perform CAM switch to C(3) photosynthesis during free-running oscillations while subjected to constant illumination. 相似文献
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Efforts to improve photosynthetic efficiency should result in increased rates of carbon assimilation in crop plants in the next few decades. Translation of increased assimilation into higher productivity will require a greater understanding of the relationship between assimilation and growth. In this review, we discuss new progress in understanding how carbon is provided for metabolism and growth at night. In Arabidopsis leaves, the circadian clock controls the rate of degradation of starch to ensure an optimal carbon supply and hence continued growth during the night. These discoveries shed new light on the integration of carbon assimilation and growth over the light-dark cycle. They reveal the importance of considering the carbon economy of the whole plant in attempting to increase crop productivity. 相似文献
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Delayed fluorescence as a universal tool for the measurement of circadian rhythms in higher plants 总被引:1,自引:0,他引:1
Peter D. Gould Patrick Diaz Claire Hogben Jelena Kusakina Radia Salem James Hartwell Anthony Hall 《The Plant journal : for cell and molecular biology》2009,58(5):893-901
The plant circadian clock plays an important role in enhancing performance and increasing vegetative yield. Much of our current understanding of the mechanism and function of the plant clock has come from the development of Arabidopsis thaliana as a model circadian organism. Key to this rapid progress has been the development of robust circadian markers, specifically circadian-regulated luciferase reporter genes. Studies of the clock in crop species and non-model organisms are currently hindered by the absence of a simple high-throughput universal assay for clock function, accuracy and robustness. Delayed fluorescence (DF) is a fundamental process occurring in all photosynthetic organisms. It is luminescence-produced post-illumination due to charge recombination in photosystem II (PSII) leading to excitation of P680 and the subsequent emission of a photon. Here we report that the amount of DF oscillates with an approximately 24-h period and is under the control of the circadian clock in a diverse selection of plants. Thus, DF provides a simple clock output that may allow the clock to be assayed in vivo in any photosynthetic organism. Furthermore, our data provide direct evidence that the nucleus-encoded, three-loop circadian oscillator underlies rhythms of PSII activity in the chloroplast. This simple, high-throughput and non-transgenic assay could be integrated into crop breeding programmes, the assay allows the selection of plants that have robust and accurate clocks, and possibly enhanced performance and vegetative yield. This assay could also be used to characterize rapidly the role and function of any novel Arabidopsis circadian mutant. 相似文献
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Isotope ratios of cellulose from plants having different photosynthetic pathways 总被引:13,自引:4,他引:9
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Hydrogen and carbon isotope ratios of cellulose nitrate and oxygen isotope ratios of cellulose from C3, C4, and Crassulacean acid metabolism (CAM) plants were determined for plants growing within a small area in Val Verde County, Texas. Plants having CAM had distinctly higher deuterium/hydrogen (D/H) ratios than plants having C3 and C4 metabolism. When hydrogen isotope ratios are plotted against carbon isotope ratios, each photosynthetic mode separates into a distinct cluster of points. C4 plants had many D/H ratios similar to those of C3 plants, so that hydrogen isotope ratios cannot be used to distinguish between these two photosynthetic modes. Portulaca mundula, which may have a modified photosynthetic mode between C4 and CAM, had a hydrogen isotope ratio between those of the C4 and CAM plants. When oxygen isotope ratios are plotted against carbon isotope ratios, no distinct clustering of the C4 and CAM plants occurs. Thus, oxygen isotope ratios are not useful in distinguishing between these metabolic modes. A plot of hydrogen isotope ratios versus oxygen isotope ratios for this sample set shows considerable overlap between oxygen isotope ratios of the different photosynthetic modes without a concomitant overlap in the hydrogen isotope ratios of CAM and the other two photosynthetic modes. This observation is consistent with the hypothesis that higher D/H ratios in CAM plants relative to C3 and C4 plants are due to isotopic fractionations occurring during biochemical reactions. 相似文献