Harnessing the dynamics of plant organic acids metabolism following abiotic stresses.

Plants encounter various environmental stresses throughout development, including shade, high light, drought, hypoxia, extreme temperatures, and metal toxicity, all of which adversely affect growth and productivity. Organic acids (OAs), besides serving as intermediates in the tricarboxylic acid (TCA) cycle, play crucial roles in multiple metabolic pathways and cellular compartments, including mitochondrial metabolism, amino acid metabolism, the glyoxylate cycle, and the photosynthetic mechanisms of C4 and CAM plants. OAs contribute to stress tolerance by acting as root chelating agents, regulating ATP production, and providing reducing power for detoxifying reactive oxygen species (ROS).

Differential content of leaf and fruit pigment in tomatoes culminate in a complex metabolic reprogramming without growth impacts.

Although significant efforts to produce carotenoid-enriched foods either by biotechnology or traditional breeding strategies have been carried out, our understanding of how changes in the carotenoid biosynthesis might affect overall plant performance remains limited. Here, we investigate how the metabolic machinery of well characterized tomato carotenoid mutant plants [namely crimson (old gold-og), Delta carotene (Del) and tangerine (t)] adjusts itself to varying carotenoid biosynthesis and whether these adjustments are supported by a reprogramming of photosynthetic and central metabolism in the source organs (leaves). We observed that mutations og, Del and t did not greatly affect vegetative growth, leaf anatomy and gas exchange parameters.

The interplay between autophagy and chloroplast vesiculation pathways under dark-induced senescence.

In cellular circumstances where carbohydrates are scarce, plants can use alternative substrates for cellular energetic maintenance. In plants, the main protein reserve is present in the chloroplast, which contains most of the total leaf proteins and represents a rich source of nitrogen and amino acids. Autophagy plays a key role in chloroplast breakdown, a well-recognised symptom of both natural and stress-induced plant senescence.

Unveiling the dark side of guard cell metabolism.

Evidence suggests that guard cells have higher rate of phosphoenolpyruvate carboxylase (PEPc)-mediated dark CO assimilation than mesophyll cells. However, it is unknown which metabolic pathways are activated following dark CO assimilation in guard cells. Furthermore, it remains unclear how the metabolic fluxes throughout the tricarboxylic acid (TCA) cycle and associated pathways are regulated in illuminated guard cells.

Efficient sugar utilization and transition from oxidative to substrate-level phosphorylation in high starch storage roots of African cassava genotypes.

Cassava's storage roots represent one of the most important sources of nutritional carbohydrates worldwide. Particularly, smallholder farmers in sub-Saharan Africa depend on this crop plant, where resilient and yield-improved varieties are of vital importance to support steadily increasing populations. Aided by a growing understanding of the plant's metabolism and physiology, targeted improvement concepts already led to visible gains in recent years.

On the Significance of the ADNT1 Carrier in under Waterlogging Conditions.

Among the adenylate carriers identified in , only the AMP/ATP transporter shows increased expression in roots under waterlogging stress conditions. Here, we investigated the impact of a reduced expression of in plants submitted to waterlogging conditions. For this purpose, an T-DNA mutant and two antisense lines were evaluated.

Nutrient availability regulates Deschampsia antarctica photosynthetic and stress tolerance performance in Antarctica.

Deschampsia antarctica is one of the only two native vascular plants in Antarctica, mostly located in the ice-free areas of the Peninsula's coast and adjacent islands. This region is characterized by a short growing season, frequent extreme climatic events, and soils with reduced nutrient availability. However, it is unknown whether its photosynthetic and stress tolerance mechanisms are affected by the availability of nutrients to deal with this particular environment.

Crop genetic diversity uncovers metabolites, elements, and gene networks predicted to be associated with high plant biomass yields in maize.

Rapid population growth and increasing demand for food, feed, and bioenergy in these times of unprecedented climate change require breeding for increased biomass production on the world's croplands. To accelerate breeding programs, knowledge of the relationship between biomass features and underlying gene networks is needed to guide future breeding efforts. To this end, large-scale multiomics datasets were created with genetically diverse maize lines, all grown in long-term organic and conventional cropping systems.

Thioredoxins regulate the metabolic fluxes throughout the tricarboxylic acid cycle and associated pathways in a light-independent manner.

The metabolic fluxes throughout the tricarboxylic acid cycle (TCAC) are inhibited in the light by the mitochondrial thioredoxin (TRX) system. However, it is unclear how this system orchestrates the fluxes throughout the TCAC and associated pathways in the dark. Here we carried out aC-HCO labelling experiment in Arabidopsis leaves from wild type (WT) and mutants lacking TRX o1 (trxo1), TRX h2 (trxh2), or both NADPH-dependent TRX reductase A and B (ntra ntrb) exposed to 0, 30 and 60 min of dark or light conditions.

Elevated carbon assimilation and metabolic reprogramming in tomato high pigment mutants support the increased production of pigments.

High pigment mutants in tomato (Solanum lycopersicum L.), a loss of function in the control of photomorphogenesis, with greater pigment production, show altered growth, greater photosynthesis, and a metabolic reprogramming. High pigment mutations cause plants to be extremely responsive to light and produce excessive pigmentation as well as fruits with high levels of health-beneficial nutrients.

The significance of WRKY45 transcription factor in metabolic adjustments during dark-induced leaf senescence.

Plants are constantly exposed to environmental changes that affect their performance. Metabolic adjustments are crucial to controlling energy homoeostasis and plant survival, particularly during stress. Under carbon starvation, coordinated reprogramming is initiated to adjust metabolic processes, which culminate in premature senescence.

13CO2 labeling kinetics in maize reveal impaired efficiency of C4 photosynthesis under low irradiance.

C4 photosynthesis allows faster photosynthetic rates and higher water and nitrogen use efficiency than C3 photosynthesis, but at the cost of lower quantum yield due to the energy requirement of its biochemical carbon concentration mechanism. It has also been suspected that its operation may be impaired in low irradiance. To investigate fluxes under moderate and low irradiance, maize (Zea mays) was grown at 550 µmol photons m-2 s-l and 13CO2 pulse-labeling was performed at growth irradiance or several hours after transfer to 160 µmol photons m-2 s-1.

Mitochondrial and peroxisomal NAD uptake are important for improved photosynthesis and seed yield under elevated CO concentrations.

As sessile organisms, plants must adapt their physiology and developmental processes to cope with challenging environmental circumstances, such as the ongoing elevation in atmospheric carbon dioxide (CO ) levels. Nicotinamide adenine dinucleotide (NAD ) is a cornerstone of plant metabolism and plays an essential role in redox homeostasis. Given that plants impaired in NAD metabolism and transport often display growth defects, low seed production and disturbed stomatal development/movement, we hypothesized that subcellular NAD distribution could be a candidate for plants to exploit the effects of CO fertilization.

Reduced auxin signalling through the cyclophilin gene DIAGEOTROPICA impacts tomato fruit development and metabolism during ripening.

Auxin is an important hormone playing crucial roles during fruit growth and ripening; however, the metabolic impact of changes in auxin signalling during tomato (Solanum lycopersicum L.) ripening remains unclear. Here, we investigated the significance of changes in auxin signalling during different stages of fruit development by analysing changes in tomato fruit quality and primary metabolism using mutants with either lower or higher auxin sensitivity [diageotropica (dgt) and entire mutants, respectively].

Maize Field Study Reveals Covaried Microbiota and Metabolic Changes in Roots over Plant Growth.

Plant roots are colonized by microorganisms from the surrounding soil that belong to different kingdoms and form a multikingdom microbial community called the root microbiota. Despite their importance for plant growth, the relationship between soil management, the root microbiota, and plant performance remains unknown. Here, we characterize the maize root-associated bacterial, fungal, and oomycetal communities during the vegetative and reproductive growth stages of four maize inbred lines and the ; phosphate transporter mutant.

The knowns and unknowns of intracellular partitioning of carbon and nitrogen, with focus on the organic acid-mediated interplay between mitochondrion and chloroplast.

The presence of specialized cellular compartments in higher plants express an extraordinary degree of intracellular organization, which provides efficient mechanisms to avoid misbalancing of the metabolism. This offers the flexibility by which plants can quickly acclimate to fluctuating environmental conditions. For that, a fine temporal and spatial regulation of metabolic pathways is required and involves several players e.

Establishment of a GC-MS-based C-positional isotopomer approach suitable for investigating metabolic fluxes in plant primary metabolism.

C-Metabolic flux analysis ( C-MFA) has greatly contributed to our understanding of plant metabolic regulation. However, the generation of detailed in vivo flux maps remains a major challenge. Flux investigations based on nuclear magnetic resonance have resolved small networks with high accuracy.

The utility of metabolomics as a tool to inform maize biology.

With the rise of high-throughput omics tools and the importance of maize and its products as food and bioethanol, maize metabolism has been extensively explored. Modern maize is still rich in genetic and phenotypic variation, yielding a wide range of structurally and functionally diverse metabolites. The maize metabolome is also incredibly dynamic in terms of topology and subcellular compartmentalization.

Two mitochondrial phosphatases, PP2c63 and Sal2, are required for posttranslational regulation of the TCA cycle in Arabidopsis.

Protein phosphorylation is a well-established post-translational mechanism that regulates protein functions and metabolic pathways. It is known that several plant mitochondrial proteins are phosphorylated in a reversible manner. However, the identities of the protein kinases/phosphatases involved in this mechanism and their roles in the regulation of the tricarboxylic acid (TCA) cycle remain unclear.

Prunus Hexokinase 3 genes alter primary C-metabolism and promote drought and salt stress tolerance in Arabidopsis transgenic plants.

Hexokinases (HXKs) and fructokinases (FRKs) are the only two families of enzymes in plants that have been identified as able to phosphorylate Glucose (Glc) and Fructose (Fru). Glc can only be phosphorylated in plants by HXKs, while Fru can be phosphorylated by either HXKs or FRKs. The various subcellular localizations of HXKs in plants indicate that they are involved in diverse functions, including anther dehiscence and pollen germination, stomatal closure in response to sugar levels, stomatal aperture and reducing transpiration.

Downregulation of the E2 Subunit of 2-Oxoglutarate Dehydrogenase Modulates Plant Growth by Impacting Carbon-Nitrogen Metabolism in Arabidopsis thaliana.

In Arabidopsis thaliana, two genes encode the E2 subunit of the 2-oxoglutarate dehydrogenase (2-OGDH), a multimeric complex composed of three subunits. To functionally characterize the isoforms of E2 subunit, we isolated Arabidopsis mutant lines for each gene encoding the E2 subunit and performed a detailed molecular and physiological characterization of the plants under controlled growth conditions. The functional lack of expression of E2 subunit isoforms of 2-OGDH increased plant growth, reduced dark respiration and altered carbohydrate metabolism without changes in the photosynthetic rate.

Changes in intracellular NAD status affect stomatal development in an abscisic acid-dependent manner.

Nicotinamide adenine dinucleotide (NAD) plays a central role in redox metabolism in all domains of life. Additional roles in regulating posttranslational protein modifications and cell signaling implicate NAD as a potential integrator of central metabolism and programs regulating stress responses and development. Here we found that NAD negatively impacts stomatal development in cotyledons of Arabidopsis thaliana.

High Photosynthetic Rates in a Chromosome 2 QTL Is Explained by Biochemical and Photochemical Changes.

Enhanced photosynthesis is strictly associated with to productivity and it can be accomplished by genetic approaches through identification of genetic variation. By using a introgression lines (ILs) population, it was previously verified that, under normal (CO), IL 2-5 and 2-6 display increased photosynthetic rates by up to 20% in comparison with their parental background (M82). However, the physiological mechanisms involved in the enhanced CO assimilation exhibited by these lines remained unknown, precluding their use for further biotechnological applications.

Downregulation of a Mitochondrial NAD+ Transporter (NDT2) Alters Seed Production and Germination in Arabidopsis.

Despite the fundamental importance of nicotinamide adenine dinucleotide (NAD+) for metabolism, the physiological roles of NAD+ carriers in plants remain unclear. We previously characterized the Arabidopsis thaliana gene (At1g25380), named AtNDT2, encoding a protein located in the mitochondrial inner membrane, which imports NAD+ from the cytosol using ADP and AMP as counter-exchange substrates for NAD+. Here, we further investigated the physiological roles of NDT2, by isolating a T-DNA insertion line, generating an antisense line and characterizing these genotypes in detail.

Eating Away at ROS to Regulate Stomatal Opening.

Although reactive oxygen species (ROS) function in guard cell signaling has been demonstrated, the control of ROS homeostasis remains elusive. Recent findings point to multiple mechanisms controlling ROS levels in guard cells. These mechanisms require secondary metabolism and autophagy, providing the guard cells with a degree of plasticity during stomatal movements.