ORCID Profile
0000-0001-8533-3004
Current Organisation
Max Planck Institute for Molecular Plant Physiology
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Plant Physiology | Plant Biology | Plant Cell and Molecular Biology | Plant Developmental and Reproductive Biology | Biological Mathematics | Intellectual Property Law | Genetically Modified Field Crops and Pasture | Population, Ecological and Evolutionary Genetics
ANZSRC Socio-Economic Objective (SEO)
Horticultural Crops not elsewhere classified | Expanding Knowledge in the Biological Sciences | Environmentally Sustainable Plant Production not elsewhere classified | Summer Grains and Oilseeds not elsewhere classified | Winter Grains and Oilseeds not elsewhere classified | Grain Legumes | Expanding Knowledge in the Agricultural and Veterinary Sciences | Expanding Knowledge in Law and Legal Studies | Expanding Knowledge in the Mathematical Sciences |
Related Links
Publications
Feedback Inhibition of Starch Degradation in Arabidopsis Leaves Mediated by Trehalose 6-Phosphate
Publisher: Oxford University Press (OUP)
Date: 16-09-2013
Abstract: Many plants accumulate substantial starch reserves in their leaves during the day and remobilize them at night to provide carbon and energy for maintenance and growth. In this paper, we explore the role of a sugar-signaling metabolite, trehalose-6-phosphate (Tre6P), in regulating the accumulation and turnover of transitory starch in Arabidopsis (Arabidopsis thaliana) leaves. Ethanol-induced overexpression of trehalose-phosphate synthase during the day increased Tre6P levels up to 11-fold. There was a transient increase in the rate of starch accumulation in the middle of the day, but this was not linked to reductive activation of ADP-glucose pyrophosphorylase. A 2- to 3-fold increase in Tre6P during the night led to significant inhibition of starch degradation. Maltose and maltotriose did not accumulate, suggesting that Tre6P affects an early step in the pathway of starch degradation in the chloroplasts. Starch granules isolated from induced plants had a higher orthophosphate content than granules from noninduced control plants, consistent either with disruption of the phosphorylation-dephosphorylation cycle that is essential for efficient starch breakdown or with inhibition of starch hydrolysis by β-amylase. Nonaqueous fractionation of leaves showed that Tre6P is predominantly located in the cytosol, with estimated in vivo Tre6P concentrations of 4 to 7 µm in the cytosol, 0.2 to 0.5 µm in the chloroplasts, and 0.05 µm in the vacuole. It is proposed that Tre6P is a component in a signaling pathway that mediates the feedback regulation of starch breakdown by sucrose, potentially linking starch turnover to demand for sucrose by growing sink organs at night.
Time-Series Transcriptomics Reveals That AGAMOUS-LIKE22 Affects Primary Metabolism and Developmental Processes in Drought-Stressed Arabidopsis
Publisher: Oxford University Press (OUP)
Date: 02-2016
DOI: 10.1105/TPC.15.00910
Evolution and Function of the Sucrose-Phosphate Synthase Gene Families in Wheat and Other Grasses
Publisher: Oxford University Press (OUP)
Date: 07-2004
Abstract: Suc-phosphate synthase (SPS) is a key regulatory enzyme in the pathway of Suc biosynthesis and has been linked to quantitative trait loci controlling plant growth and yield. In dicotyledonous plants there are three SPS gene families: A, B, and C. Here we report the finding of five families of SPS genes in wheat (Triticum aestivum) and other monocotyledonous plants from the family Poaceae (grasses). Three of these form separate subfamilies within the previously described A, B, and C gene families, but the other two form a novel and distinctive D family, which on present evidence is only found in the Poaceae. The D-type SPS proteins lack the phosphorylation sites associated with 14-3-3 protein binding and osmotic stress activation, and the linker region between the N-terminal catalytic glucosyltransferase domain and the C-terminal Suc-phosphatase-like domain is 80 to 90 amino acid residues shorter than in the A, B, or C types. The D family appears to have arisen after the ergence of mono- and dicotyledonous plants, with a later duplication event resulting in the two D-type subfamilies. Each of the SPS gene families in wheat showed different, but overlapping, spatial and temporal expression patterns, and in most organs at least two different SPS genes are expressed. Analysis of expressed sequence tags indicated similar expression patterns to wheat for each SPS gene family in barley (Hordeum vulgare) but not in more distantly related grasses. We identified an expressed sequence tag from rice (Oryza sativa) that appears to be derived from an endogenous antisense SPS gene, and this might account for the apparently low level of expression of the related OsSPS11 sense gene, adding to the already extensive list of mechanisms for regulating the activity of SPS in plants.
Metabolic profiles in C3, C3–C4 intermediate, C4-like, and C4 species in the genus Flaveria
Publisher: Oxford University Press (OUP)
Date: 15-12-2021
DOI: 10.1093/JXB/ERAB540
Abstract: C4 photosynthesis concentrates CO2 around Rubisco in the bundle sheath, favouring carboxylation over oxygenation and decreasing photorespiration. This complex trait evolved independently in & angiosperm lineages. Its evolution can be investigated in genera such as Flaveria (Asteraceae) that contain species representing intermediate stages between C3 and C4 photosynthesis. Previous studies have indicated that the first major change in metabolism probably involved relocation of glycine decarboxylase and photorespiratory CO2 release to the bundle sheath and establishment of intercellular shuttles to maintain nitrogen stoichiometry. This was followed by selection for a CO2-concentrating cycle between phosphoenolpyruvate carboxylase in the mesophyll and decarboxylases in the bundle sheath, and relocation of Rubisco to the latter. We have profiled 52 metabolites in nine Flaveria species and analysed 13CO2 labelling patterns for four species. Our results point to operation of multiple shuttles, including movement of aspartate in C3–C4 intermediates and a switch towards a malate yruvate shuttle in C4-like species. The malate yruvate shuttle increases from C4-like to complete C4 species, accompanied by a rise in ancillary organic acid pools. Our findings support current models and uncover further modifications of metabolism along the evolutionary path to C4 photosynthesis in the genus Flaveria.
Regulation of sucrose-phosphate synthase in wheat (Triticum aestivum) leaves
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/FP04038
Abstract: The regulation of sucrose-phosphate synthase (SPS, E.C. 2.4.1.14), a key enzyme of sucrose synthesis, was investigated in wheat (Triticum aestivum L.) leaves. Wheat SPS was activated in the light, with an increased affinity for its substrates and the activator glucose-6-phosphate, reduced sensitivity to inhibition by Pi, but no change in maximum catalytic activity. Based on these properties, assays to measure the total activity and activation state of the enzyme were established and validated using several different wheat cultivars, grown under different environmental conditions. As found in previous studies on other species, e.g. spinach, activation appeared to be linked to the prevailing rate of photosynthesis rather than light per se. Long-term exposure to higher light levels increased total SPS activity in the leaves, and some experiments indicated that this response could occur within 1 h of exposure of low-light-grown plants to high light. However, activation of pre-existing enzyme was a more common short-term response to high light. Wheat, like many important cereal species, stores a large amount of sucrose in its leaves. In contrast with spinach, which stores more starch in its leaves, accumulation of sucrose in wheat leaves did not lead to inactivation of SPS or inhibition of sucrose synthesis. In conclusion, the mechanisms linking the rates of sucrose synthesis and photosynthetic CO2 fixation in wheat leaves appear to be similar to those in other species, but the mechanisms involved in short-term feedback inhibition of sucrose synthesis by sucrose, found in starch-storing species, are lacking in wheat.
Singlet oxygen-induced signalling depends on the metabolic status of the Chlamydomonas cell
Publisher: Cold Spring Harbor Laboratory
Date: 04-11-2021
DOI: 10.1101/2021.11.03.467076
Abstract: Using a novel mutant screen, we identified TREHALOSE 6-PHOSPHATE PHOSPHATASE 1 (TSPP1) as a functional enzyme dephosphorylating trehalose 6-phosphate (Tre6P) to trehalose in Chlamydomonas reinhardtii . The tspp1 knock-out results in reprogramming of the cell metabolism via significantly altered transcriptome. As a secondary effect, tspp1 also shows impairment in 1 O 2 -induced chloroplast retrograde signalling. From transcriptomic analysis and metabolite profiling, we conclude that accumulation or deficiency of certain metabolites directly affect 1 O 2 -signalling. 1 O 2 -inducible GLUTATHIONE PEROXIDASE 5 ( GPX5 ) gene expression is suppressed by increased content of fumarate, an intermediate in the tricarboxylic acid cycle (TCA cycle) in mitochondria and dicarboxylate metabolism in the cytosol, while it is promoted by another TCA cycle intermediate, aconitate. Furthermore, genes encoding known essential components of chloroplast-to-nucleus 1 O 2 -signalling, PSBP2, MBS, and SAK1, show decreased transcript levels in the tspp1 mutant, which can be rescued by exogenous application of aconitate. We demonstrate that chloroplast retrograde signalling involving 1 O 2 depends on mitochondrial and cytosolic processes and that the metabolic status of the cell determines the response to 1 O 2 .
Genetic manipulation of trehalose‐6‐phosphate synthase results in changes in the soluble sugar profile in transgenic sugarcane stems
Publisher: Wiley
Date: 11-2021
DOI: 10.1002/PLD3.358
Abstract: Trehalose is a non‐reducing disaccharide widely distributed in nature. The trehalose biosynthetic intermediate, trehalose 6‐phosphate (Tre6P) is an essential regulatory and signaling molecule involved in both regulation of carbon metabolism and photosynthesis. To investigate the effect of altered trehalose synthesis on sucrose accumulation in sugarcane ( Saccharum spp . hybrid), we independently overexpressed the Escherichia coli otsA (trehalose‐6‐phosphate synthase TPS) and otsB (trehalose‐6‐phosphate phosphatase TPP) genes and additionally partially silenced native TPS expression. In mature cane, sucrose levels in the otsA transgenic plants were lowered, whereas sucrose levels in the otsB transgenic plants were increased. Partial silencing of TPS expression in sugarcane transformed with a TPS‐targeted microRNA recombinant construct was confirmed in leaf and mature internode tissue of transgenic plants. Most of the silencing transgenic lines accumulated trehalose at lower levels than the wild‐type (WT) plants. The immature stalk tissue of these transgenic lines had lower levels of glucose and fructose, whereas the mature internode tissue had lower sucrose and glucose levels, when compared with the WT. Furthermore, various minor metabolites and sugars were detected in the sugarcane plants, which mostly decreased as the stalk tissue of the cane matured. The results demonstrate that manipulation of Tre6P/trehalose metabolism has the potential to modify the profile of soluble sugars accumulated in sugarcane stems.
Multiple circadian clock outputs regulate diel turnover of carbon and nitrogen reserves
Publisher: Wiley
Date: 17-01-2019
DOI: 10.1111/PCE.13440
Abstract: Plants accumulate reserves in the daytime to support growth at night. Circadian regulation of diel reserve turnover was investigated by profiling starch, sugars, glucose 6-phosphate, organic acids, and amino acids during a light-dark cycle and after transfer to continuous light in Arabidopsis wild types and in mutants lacking dawn (lhy cca1), morning (prr7 prr9), dusk (toc1, gi), or evening (elf3) clock components. The metabolite time series were integrated with published time series for circadian clock transcripts to identify circadian outputs that regulate central metabolism. (a) Starch accumulation was slower in elf3 and prr7 prr9. It is proposed that ELF3 positively regulates starch accumulation. (b) Reducing sugars were high early in the T-cycle in elf3, revealing that ELF3 negatively regulates sucrose recycling. (c) The pattern of starch mobilization was modified in all five mutants. A model is proposed in which dawn and dusk/evening components interact to pace degradation to anticipated dawn. (d) An endogenous oscillation of glucose 6-phosphate revealed that the clock buffers metabolism against the large influx of carbon from photosynthesis. (e) Low levels of organic and amino acids in lhy cca1 and high levels in prr7 prr9 provide evidence that the dawn components positively regulate the accumulation of amino acid reserves.
Regulation of shoot branching in arabidopsis by trehalose 6‐phosphate
Publisher: Wiley
Date: 25-11-2020
DOI: 10.1111/NPH.17006
A developing Setaria viridis internode: an experimental system for the study of biomass generation in a C4 model species
Publisher: Springer Science and Business Media LLC
Date: 24-02-2016
Restriction of cytosolic sucrose hydrolysis profoundly alters development, metabolism, and gene expression in Arabidopsis roots
Publisher: Oxford University Press (OUP)
Date: 30-12-2020
DOI: 10.1093/JXB/ERAA581
Abstract: Plant roots depend on sucrose imported from leaves as the substrate for metabolism and growth. Sucrose and hexoses derived from it are also signalling molecules that modulate growth and development, but the importance for signalling of endogenous changes in sugar levels is poorly understood. We report that reduced activity of cytosolic invertase, which converts sucrose to hexoses, leads to pronounced metabolic, growth, and developmental defects in roots of Arabidopsis (Arabidopsis thaliana) seedlings. In addition to altered sugar and downstream metabolite levels, roots of cinv1 cinv2 mutants have reduced elongation rates, cell and meristem size, abnormal meristematic cell ision patterns, and altered expression of thousands of genes of erse functions. Provision of exogenous glucose to mutant roots repairs relatively few of the defects. The extensive transcriptional differences between mutant and wild-type roots have hallmarks of both high sucrose and low hexose signalling. We conclude that the mutant phenotype reflects both low carbon availability for metabolism and growth and complex sugar signals derived from elevated sucrose and depressed hexose levels in the cytosol of mutant roots. Such reciprocal changes in endogenous sucrose and hexose levels potentially provide rich information about sugar status that translates into flexible adjustments of growth and development.
Leaf Starch Turnover Occurs in Long Days and in Falling Light at the End of the Day
Publisher: Oxford University Press (OUP)
Date: 29-06-2017
DOI: 10.1104/PP.17.00601
Ready, steady, go! A sugar hit starts the race to shoot branching
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.PBI.2015.04.004
Abstract: In the classical theory of apical dominance, auxin depletion from the stem releases bud dormancy. Recent studies have revealed a poor correlation between the initial bud release and auxin depletion from the stem after decapitation. Sucrose mobility in plants and its accumulation in buds correlates well with the onset of bud release and is able to trigger bud outgrowth. The ersion of sugars away from axillary buds decreases bud release even where hormones are at levels generally considered conducive to bud release. This impact of sugars on bud outgrowth may be mediated by specific sugar and hormonal signalling pathways.
The transcription factor bZIP11 acts antagonistically with trehalose 6-phosphate to inhibit shoot branching
Publisher: Cold Spring Harbor Laboratory
Date: 24-05-2023
DOI: 10.1101/2023.05.23.542007
Abstract: The ontogenetic regulation of shoot branching allows plants to adjust their architecture in accordance with the environment. This process is due to the regulation of axillary bud outgrowth into branches, which can be induced by increasing sugar availability to the buds through decapitation of the shoot tip. Different sugar signalling components have been identified in the induction of shoot branching. However, the molecular components that maintain bud dormancy in response to sugar starvation remain largely unknown. Here, we show at the genetic level that basic leucine zipper 11 (bZIP11), a transcription factor that plays important roles in response to sugar starvation in plants, inhibits shoot branching in Arabidopsis thaliana . Physiology experiments demonstrated that bZIP11 protein levels are decreased by decapitation. Molecular and genetic evidence suggests that bZIP11 acts in a negative feedback loop with trehalose 6-phosphate (Tre6P), a sugar signal that promotes shoot branching. Our data also suggest that the central energy sensor SUCROSE NON-FERMENTING 1 RELATED KINASE1 (SnRK1), alleviates the inhibitory effect of Tre6P on bZIP11 protein accumulation and inhibits shoot branching. Altogether, these data provide a working model that involves bZIP11, Tre6P and SnRK1 in the regulation of shoot branching.
Trehalose 6‐phosphate is involved in triggering axillary bud outgrowth in garden pea (Pisum sativum L.)
Publisher: Wiley
Date: 06-10-2017
DOI: 10.1111/TPJ.13705
Abstract: Trehalose 6-phosphate (Tre6P) is a signal of sucrose availability in plants, and has been implicated in the regulation of shoot branching by the abnormal branching phenotypes of Arabidopsis (Arabidopsis thaliana) and maize (Zea mays) mutants with altered Tre6P metabolism. Decapitation of garden pea (Pisum sativum) plants has been proposed to release the dormancy of axillary buds lower down the stem due to changes in sucrose supply, and we hypothesized that this response is mediated by Tre6P. Decapitation led to a rapid and sustained rise in Tre6P levels in axillary buds, coinciding with the onset of bud outgrowth. This response was suppressed by simultaneous defoliation that restricts the supply of sucrose to axillary buds in decapitated plants. Decapitation also led to a rise in amino acid levels in buds, but a fall in phosphoenolpyruvate and 2-oxoglutarate. Supplying sucrose to stem node explants in vitro triggered a concentration-dependent increase in the Tre6P content of the buds that was highly correlated with their rate of outgrowth. These data show that changes in bud Tre6P levels are correlated with initiation of bud outgrowth following decapitation, suggesting that Tre6P is involved in the release of bud dormancy by sucrose. Tre6P might also be linked to a reconfiguration of carbon and nitrogen metabolism to support the subsequent growth of the bud into a new shoot.
Carbon Supply and the Regulation of Cell Wall Synthesis
Publisher: Elsevier BV
Date: 2018
DOI: 10.1016/J.MOLP.2017.10.004
Abstract: All plant cells are surrounded by a cell wall that determines the directionality of cell growth and protects the cell against its environment. Plant cell walls are comprised primarily of polysaccharides and represent the largest sink for photosynthetically fixed carbon, both for in idual plants and in the terrestrial biosphere as a whole. Cell wall synthesis is a highly sophisticated process, involving multiple enzymes and metabolic intermediates, intracellular trafficking of proteins and cell wall precursors, assembly of cell wall polymers into the extracellular matrix, remodeling of polymers and their interactions, and recycling of cell wall sugars. In this review we discuss how newly fixed carbon, in the form of UDP-glucose and other nucleotide sugars, contributes to the synthesis of cell wall polysaccharides, and how cell wall synthesis is influenced by the carbon status of the plant, with a focus on the model species Arabidopsis (Arabidopsis thaliana).
Purification, molecular cloning, and sequence analysis of sucrose-6 F -phosphate phosphohydrolase from plants
Publisher: Proceedings of the National Academy of Sciences
Date: 24-10-2000
Abstract: Sucrose-6 F -phosphate phosphohydrolase (SPP EC 3.1.3.24 ) catalyzes the final step in the pathway of sucrose biosynthesis and is the only enzyme of photosynthetic carbon assimilation for which the gene has not been identified. The enzyme was purified to homogeneity from rice ( Oryza sativa L.) leaves and partially sequenced. The rice leaf enzyme is a dimer with a native molecular mass of 100 kDa and a subunit molecular mass of 50 kDa. The enzyme is highly specific for sucrose 6 F -phosphate with a K m of 65 μM and a specific activity of 1250 μmol min −1 mg −1 protein. The activity is dependent on Mg 2+ with a remarkably low K a of 8–9 μM and is weakly inhibited by sucrose. Three peptides from cleavage of the purified rice SPP with endoproteinase Lys-C showed similarity to the deduced amino acid sequences of three predicted open reading frames (ORF) in the Arabidopsis thaliana genome and one in the genome of the cyanobacterium Synechocystis sp. PCC6803, as well as cDNA clones from Arabidopsis , maize, and other species in the GenBank database of expressed sequence tags. The putative maize SPP cDNA clone contained an ORF encoding a 420-amino acid polypeptide. Heterologous expression in Escherichia coli showed that this cDNA clone encoded a functional SPP enzyme. The 260-amino acid N-terminal catalytic domain of the maize SPP is homologous to the C-terminal region of sucrose-phosphate synthase. A PSI-BLAST search of the GenBank database indicated that the maize SPP is a member of the haloacid dehalogenase hydrolase hosphatase superfamily.
The sucrose–trehalose 6-phosphate (Tre6P) nexus: specificity and mechanisms of sucrose signalling by Tre6P
Publisher: Oxford University Press (OUP)
Date: 13-01-2014
DOI: 10.1093/JXB/ERT457
Singlet oxygen-induced signalling depends on the metabolic status of the Chlamydomonas reinhardtii cell
Publisher: Springer Science and Business Media LLC
Date: 16-05-2023
DOI: 10.1038/S42003-023-04872-5
Abstract: Using a mutant screen, we identified trehalose 6-phosphate phosphatase 1 (TSPP1) as a functional enzyme dephosphorylating trehalose 6-phosphate (Tre6P) to trehalose in Chlamydomonas reinhardtii . The tspp1 knock-out results in reprogramming of the cell metabolism via altered transcriptome. As a secondary effect, tspp1 also shows impairment in 1 O 2 -induced chloroplast retrograde signalling. From transcriptomic analysis and metabolite profiling, we conclude that accumulation or deficiency of certain metabolites directly affect 1 O 2 -signalling. 1 O 2 -inducible GLUTATHIONE PEROXIDASE 5 ( GPX5 ) gene expression is suppressed by increased content of fumarate and 2-oxoglutarate, intermediates in the tricarboxylic acid cycle (TCA cycle) in mitochondria and dicarboxylate metabolism in the cytosol, but also myo-inositol, involved in inositol phosphate metabolism and phosphatidylinositol signalling system. Application of another TCA cycle intermediate, aconitate, recovers 1 O 2 -signalling and GPX5 expression in otherwise aconitate-deficient tspp1 . Genes encoding known essential components of chloroplast-to-nucleus 1 O 2 -signalling, PSBP2, MBS, and SAK1, show decreased transcript levels in tspp1 , which also can be rescued by exogenous application of aconitate. We demonstrate that chloroplast retrograde signalling involving 1 O 2 depends on mitochondrial and cytosolic processes and that the metabolic status of the cell determines the response to 1 O 2 .
Installation of C4 photosynthetic pathway enzymes in rice using a single construct
Publisher: Wiley
Date: 27-10-2020
DOI: 10.1111/PBI.13487
Functional Features of TREHALOSE-6-PHOSPHATE SYNTHASE1, an Essential Enzyme in Arabidopsis[OPEN]
Publisher: Oxford University Press (OUP)
Date: 10-04-2020
DOI: 10.1105/TPC.19.00837
Abstract: In Arabidopsis (Arabidopsis thaliana), TREHALOSE-6-PHOSPHATE SYNTHASE1 (TPS1) catalyzes the synthesis of the sucrose-signaling metabolite trehalose 6-phosphate (Tre6P) and is essential for embryogenesis and normal postembryonic growth and development. To understand its molecular functions, we transformed the embryo-lethal tps1-1 null mutant with various forms of TPS1 and with a heterologous TPS (OtsA) from Escherichia coli, under the control of the TPS1 promoter, and tested for complementation. TPS1 protein localized predominantly in the phloem-loading zone and guard cells in leaves, root vasculature, and shoot apical meristem, implicating it in both local and systemic signaling of Suc status. The protein is targeted mainly to the nucleus. Restoring Tre6P synthesis was both necessary and sufficient to rescue the tps1-1 mutant through embryogenesis. However, postembryonic growth and the sucrose-Tre6P relationship were disrupted in some complementation lines. A point mutation (A119W) in the catalytic domain or truncating the C-terminal domain of TPS1 severely compromised growth. Despite having high Tre6P levels, these plants never flowered, possibly because Tre6P signaling was disrupted by two unidentified disaccharide-monophosphates that appeared in these plants. The noncatalytic domains of TPS1 ensure its targeting to the correct subcellular compartment and its catalytic fidelity and are required for appropriate signaling of Suc status by Tre6P.
Regulatory Properties of ADP Glucose Pyrophosphorylase Are Required for Adjustment of Leaf Starch Synthesis in Different Photoperiods
Publisher: Oxford University Press (OUP)
Date: 07-10-2014
Abstract: Arabidopsis (Arabidopsis thaliana) leaves synthesize starch faster in short days than in long days, but the mechanism that adjusts the rate of starch synthesis to daylength is unknown. To understand this mechanism, we first investigated whether adjustment occurs in mutants lacking components of the circadian clock or clock output pathways. Most mutants adjusted starch synthesis to daylength, but adjustment was compromised in plants lacking the GIGANTEA or FLAVIN-BINDING, KELCH REPEAT, F BOX1 components of the photoperiod-signaling pathway involved in flowering. We then examined whether the properties of the starch synthesis enzyme adenosine 5′-diphosphate-glucose pyrophosphorylase (AGPase) are important for adjustment of starch synthesis to daylength. Modulation of AGPase activity is known to bring about short-term adjustments of photosynthate partitioning between starch and sucrose (Suc) synthesis. We found that adjustment of starch synthesis to daylength was compromised in plants expressing a deregulated bacterial AGPase in place of the endogenous AGPase and in plants containing mutant forms of the endogenous AGPase with altered allosteric regulatory properties. We suggest that the rate of starch synthesis is in part determined by growth rate at the end of the preceding night. If growth at night is low, as in short days, there is a delay before growth recovers during the next day, leading to accumulation of Suc and stimulation of starch synthesis via activation of AGPase. If growth at night is fast, photosynthate is used for growth at the start of the day, Suc does not accumulate, and starch synthesis is not up-regulated.
The role of Tre6P and SnRK1 in maize early kernel development and events leading to stress-induced kernel abortion
Publisher: Springer Science and Business Media LLC
Date: 12-04-2017
S1basic leucine zipper transcription factors shape plant architecture by controlling C/N partitioning to apical and lateral organs
Publisher: Cold Spring Harbor Laboratory
Date: 24-05-2023
DOI: 10.1101/2023.05.23.541964
Abstract: Plants exhibit an immense plasticity in their architecture. While the impact of hormonal regulation is well-characterised, the importance of sugar-signalling has just recently emerged. Here, we addressed which sugar-signalling components mediate the trade-off between growth of apical versus lateral meristems and how they control organ sink-strength. Thereby, we unravelled a novel developmental function of the sugar-controlled S 1 basic-leucine-zipper (S 1 -bZIP) transcription factors in establishing global source-sink interactions. Applying comprehensive molecular, analytical, and genetic approaches, we demonstrate that S 1 -bZIPs operate in a redundant manner to control tissue-specific expression of defined SWEET sugar-transporters and the GAT1_2.1 glutaminase. By these means, S 1 -bZIPs control carbohydrate (C)-channelling from source leaves to apical shoot and root organs and tune systemic organic nitrogen (N)-supply to restrict lateral organ formation by C/N depletion. Knowledge of the underlying mechanisms controlling plant C/N partitioning is of pivotal importance for breeding strategies to generate plants with desired architectural and nutritional characteristics.
The role of trehalose 6-phosphate in shoot branching – local and non-local effects on axillary bud outgrowth in arabidopsis rosettes
Publisher: Cold Spring Harbor Laboratory
Date: 19-06-2020
DOI: 10.1101/2020.06.18.158568
Abstract: - Trehalose 6-phosphate (Tre6P) is a sucrose signalling metabolite that has been implicated in regulation of shoot branching, but its precise role is not understood. - We expressed tagged forms of TREHALOSE-6-PHOSPHATE SYNTHASE1 (TPS1) to determine where Tre6P is synthesized in arabidopsis ( Arabidopsis thaliana ), and investigated the impact of localized changes in Tre6P levels, in axillary buds or vascular tissues, on shoot branching in wild-type and branching mutant backgrounds. - TPS1 is expressed in axillary buds and the subtending vasculature, as well as in the leaf and stem vasculature. Expression of a heterologous trehalose-6-phosphate phosphatase (TPP) to lower Tre6P in axillary buds strongly delayed bud outgrowth in long days and inhibited branching in short days. TPP expression in the vasculature also delayed lateral bud outgrowth and decreased branching. Increased Tre6P in the vasculature enhanced branching and was accompanied by higher expression of FLOWERING LOCUS T ( FT) and up-regulation of sucrose transporters. Increased vascular Tre6P levels enhanced branching in branched1 but not in ft mutant backgrounds. - These results provide direct genetic evidence of a local role for Tre6P in regulation of axillary bud outgrowth within the buds themselves, and also connect Tre6P with systemic regulation of shoot branching via FT.
Arabidopsis Coordinates the Diurnal Regulation of Carbon Allocation and Growth across a Wide Range of Photoperiods
Publisher: Elsevier BV
Date: 2014
DOI: 10.1093/MP/SST127
Abstract: In short photoperiods, plants accumulate starch more rapidly in the light and degrade it more slowly at night, ensuring that their starch reserves last until dawn. To investigate the accompanying changes in the timing of growth, Arabidopsis was grown in a range of photoperiods and analyzed for rosette biomass, photosynthesis, respiration, ribosome abundance, polysome loading, starch, and over 40 metabolites at dawn and dusk. The data set was used to model growth rates in the daytime and night, and to identify metabolites that correlate with growth. Modeled growth rates and polysome loading were high in the daytime and at night in long photoperiods, but decreased at night in short photoperiods. Ribosome abundance was similar in all photoperiods. It is discussed how the amount of starch accumulated in the light period, the length of the night, and maintenance costs interact to constrain growth at night in short photoperiods, and alter the strategy for optimizing ribosome use. Significant correlations were found in the daytime and the night between growth rates and the levels of the sugar-signal trehalose 6-phosphate and the amino acid biosynthesis intermediate shikimate, identifying these metabolites as hubs in a network that coordinates growth with diurnal changes in the carbon supply.
Metabolite profiles reveal interspecific variation in operation of the Calvin–Benson cycle in both C4 and C3 plants
Publisher: Oxford University Press (OUP)
Date: 18-02-2019
DOI: 10.1093/JXB/ERZ051
Related Organisations
Max Planck Institute For Molecular Plant Physiology
Location: Germany
University Of Cambridge
Location: United Kingdom of Great Britain and Northern Ireland
Related Funding Activities
Discovery Projects - Grant ID: DP180101047
Start Date: 07-2018
End Date: 07-2018
Amount: $383,136.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP150101037
Start Date: 2015
End Date: 06-2018
Amount: $438,700.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP150102086
Start Date: 2015
End Date: 12-2017
Amount: $386,700.00
Funder: Australian Research Council
View Funded ActivityARC Centres Of Excellence - Grant ID: CE200100015
Start Date: 12-2020
End Date: 12-2027
Amount: $35,000,000.00
Funder: Australian Research Council
View Funded Activity