Vacuolar transporters and their essential role in plant metabolism

Following the unequivocal demonstration that plants contain at least two types of vacuoles, scientists studying this organelle have realized that the plant ‘vacuome' is far more complex than they expected. Some fully developed cells contain at least two large vacuoles, with different functions. Remarkably, even a single vacuole may be subdivided and fulfil several functions, which are supported in part by the vacuolar membrane transport systems. Recent studies, including proteomic analyses for several plant species, have revealed the tonoplast transporters and their involvement in the nitrogen storage, salinity tolerance, heavy metal homeostasis, calcium signalling, guard cell movements, and the cellular pH homeostasis. It is clear that vacuolar transporters are an integrated part of a complex cellular network that enables a plant to react properly to changing environmental conditions, to save nutrients and energy in times of plenty, and to maintain optimal metabolic conditions in the cytosol. An overview is given of the main features of the transporters present in the tonoplast of plant cells in terms of their function, regulation, and relationships with the microheterogeneity of the vacuom

In vitro analyses of mitochondrial ATP/phosphate carriers from Arabidopsis thaliana revealed unexpected Ca2+-effects

Background: Adenine nucleotide/phosphate carriers (APCs) from mammals and yeast are commonly known to adapt the mitochondrial adenine nucleotide pool in accordance to cellular demands. They catalyze adenine nucleotide - particularly ATP-Mg - and phosphate exchange and their activity is regulated by calcium. Our current knowledge about corresponding proteins from plants is comparably limited. Recently, the three putative APCs from Arabidopsis thaliana were shown to restore the specific growth phenotype of APC yeast loss-of-function mutants and to interact with calcium via their N-terminal EF-hand motifs in vitro. In this study, we performed biochemical characterization of all three APC isoforms from A. thaliana to gain further insights into their functional properties. Results: Recombinant plant APCs were functionally reconstituted into liposomes and their biochemical characteristics were determined by transport measurements using radiolabeled substrates. All three plant APCs were capable of ATP, ADP and phosphate exchange, however, high preference for ATP-Mg, as shown for orthologous carriers, was not detectable. By contrast, the obtained data suggest that in the liposomal system the plant APCs rather favor ATP-Ca as substrate. Moreover, investigation of a representative mutant APC protein revealed that the observed calcium effects on ATP transport did not primarily/essentially involve Ca2+-binding to the EF-hand motifs in the N-terminal domain of the carrier. Conclusion: Biochemical characteristics suggest that plant APCs can mediate net transport of adenine nucleotides and hence, like their pendants from animals and yeast, might be involved in the alteration of the mitochondrial adenine nucleotide pool. Although, ATP-Ca was identified as an apparent import substrate of plant APCs in vitro it is arguable whether ATP-Ca formation and thus the corresponding transport can take place in vivo

Quantitation of Vacuolar Sugar Transporter Abundance Changes Using QconCAT Synthtetic Peptides

Measurements of protein abundance changes are important for biological conclusions on protein-related processes such as activity or complex formation. Proteomic analyses in general are almost routine tasks in many laboratories, but a precise and quantitative description of (absolute) protein abundance changes require careful experimental design and precise data quality. Today, a vast choice of metabolic labeling and label free quantitation protocols are available, but the trade-off between quantitative precision and proteome coverage of quantified proteins including missing value problems remain. Here, we provide an example of a targeted proteomic approach using artificial standard proteins consisting of concatenated peptides of interest (QconCAT) to specifically quantify abiotic stress-induced abundance changes in low abundant vacuolar transporters. An advantage of this approach is the reliable quantitation of alimited set of low-abundant target proteins throughout different conditions. We show that vacuolar ATPase AVP1 and sugar transporters of the ERDL (early responsive to dehydration-like) family and TMT2 (tonoplast monosaccharide transporter 2) showed increased abundance upon salt stress

Оценка экономической эффективности инновационного проекта в IT-сфере

Цель работы - разработка комплекса мероприятий по совершенствованию проектной деятельности в IT-сфере (на примере IT-проекта "UMKA"). В процессе исследования проводились изучения теоретических основ проектной деятельности компании, особенности реализации инновационных проектов в IT-сфере, анализировались модели, методы и показатели оценки эффективности IT-проекта, выявлялись особенности оценки эффективности проектов в IT-сфере. В практической части проводилась оценка эффективности IT-проекта "UMKA", разработанная и реализуемая ООО "I-link".The work purpose - development of complex of measures on improvement of project activities in the IT sphere (on the example of an IT project "UMKA"). In the process of research was conducted to study the theoretical basics of project activities of the company, peculiarities of realization of innovative projects in the IT field, we have analyzed the models, methods and indicators to measure the effectiveness of an IT project and identified the features of estimation of efficiency of projects in the IT sphere. In the practical part of the evaluation of the effectiveness of IT-project "UMKA", developed and implemented by "I-link"

14-3-3 Proteins and Other Candidates form Protein-Protein Interactions with the Cytosolic C-terminal End of SOS1 Affecting Its Transport Activity

The plasma membrane transporter SOS1 (SALT-OVERLY SENSITIVE1) is vital for plant survival under salt stress. SOS1 activity is tightly regulated, but little is known about the underlying mechanism. SOS1 contains a cytosolic, autoinhibitory C-terminal tail (abbreviated as SOS1 C-term), which is targeted by the protein kinase SOS2 to trigger its transport activity. Here, to identify additional binding proteins that regulate SOS1 activity, we synthesized the SOS1 C-term domain and used it as bait to probe Arabidopsis thaliana cell extracts. Several 14-3-3 proteins, which function in plant salt tolerance, specifically bound to and interacted with the SOS1 C-term. Compared to wild-type plants, when exposed to salt stress, Arabidopsis plants overexpressing SOS1 C-term showed improved salt tolerance, significantly reduced Na+ accumulation in leaves, reduced induction of the salt-responsive gene WRKY25, decreased soluble sugar, starch, and proline levels, less impaired inflorescence formation and increased biomass. It appears that overexpressing SOS1 C-term leads to the sequestration of inhibitory 14-3-3 proteins, allowing SOS1 to be more readily activated and leading to increased salt tolerance. We propose that the SOS1 C-term binds to previously unknown proteins such as 14-3-3 isoforms, thereby regulating salt tolerance. This finding uncovers another regulatory layer of the plant salt tolerance program

Synchronization of developmental, molecular and metabolic aspects of source–sink interactions

Plants have evolved a multitude of strategies to adjust their growth according to external and internal signals. Interconnected metabolic and phytohormonal signalling networks allow adaption to changing environmental and developmental conditions and ensure the survival of species in fluctuating environments. In agricultural ecosystems, many of these adaptive responses are not required or may even limit crop yield, as they prevent plants from realizing their fullest potential. By lifting source and sink activities to their maximum, massive yield increases can be foreseen, potentially closing the future yield gap resulting from an increasing world population and the transition to a carbon-neutral economy. To do so, a better understanding of the interplay between metabolic and developmental processes is required. In the past, these processes have been tackled independently from each other, but coordinated efforts are required to understand the fine mechanics of source–sink relations and thus optimize crop yield. Here, we describe approaches to design high-yielding crop plants utilizing strategies derived from current metabolic concepts and our understanding of the molecular processes determining sink development.Research in the authors’ laboratories was supported by the following grants: the cassava source–sink (CASS) project of the Bill and Melinda Gates Foundation (to A.R.F., H.E.N., M.S. and U.S.); the ERA-CAPs project SourSi (to A.R.F. and L.J.S.); the BIO2015-3019-EXP grant from the Spanish Ministry of Economy, Industry and Competitiveness and the PCIN-2017-032 CONCERT-JAPAN project financed by the Ministry of Science, Innovation and Universities (to S.P.); Australian Research Council DP180103834 (to Y.L.R.); the US National Science Foundation (grant no. IOS-1457183); the Agriculture and Food Research Initiative (AFRI; grant no. 2017-67013-26158) from the USDA National Institute of Food and Agriculture (to M.T.); the Finnish Centre of Excellence in Molecular Biology of Primary Producers (Academy of Finland CoE program 2014–2019; grant no. 271832); the Gatsby Foundation (grant no. GAT3395/PR3); the University of Helsinki (grant no. 799992091); the European Research Council Advanced Investigator Grant SYMDEV (grant no. 323052; to Y.H.); the BMBF (grant no. 031B0191); the DFG (SPP1530: WA3639/1-2, 2-1); and the Max-Planck-Society (to V.W.). We additionally thank D. Ko and R. Ruonala for their comments on the manuscript

Profiling carbohydrate composition, biohydrogen capacity, and disease resistance in potato

Background: Potato ( Solanum tuberosum ) is one of the most important sources of carbohydrates in human diet. Because of its high carbohydrate levels it recently has also received attention in biohydrogen production. To exploit the natural variation of potato with respect to resistance to major diseases, carbohydrate levels and composition, and capacity for biohydrogen production we analyzed tubers of native, improved, and genetically modified potatoes, and two other tuberous species for their glucose, fructose, sucrose, and starch content. Results: High-starch potato varieties were evaluated for their potential for Caldicellulosiruptor saccharolyticus -mediated biohydrogen production with Desir\ue9e and Rosita varieties delivering the highest biohydrogen amounts. Native line Vega1 and improved line Yagana were both immune to two isolates (A291, A287) of Phytophthora infestans . Conclusions: Our data demonstrate that native potato varieties might have great potential for further improving the multifaceted use of potato in worldwide food and biohydrogen production