ORCID Profile
0000-0001-9598-2227
Current Organisation
Université Laval
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Publisher: MyJove Corporation
Date: 22-08-2014
DOI: 10.3791/51877
Publisher: Informa UK Limited
Date: 07-2013
DOI: 10.4161/PSB.24799
Publisher: Springer Science and Business Media LLC
Date: 22-06-2013
Publisher: Elsevier BV
Date: 07-2021
Publisher: Public Library of Science (PLoS)
Date: 27-02-2013
Publisher: Oxford University Press (OUP)
Date: 23-09-2011
DOI: 10.1093/JXB/ERR267
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.JPLPH.2016.05.016
Abstract: Carbon dioxide (CO
Publisher: Frontiers Media SA
Date: 18-07-2016
Publisher: Springer Science and Business Media LLC
Date: 06-06-2017
Abstract: The nitrogen (N)-use efficiency of agricultural plants is notoriously poor. Globally, about 50% of the N fertilizer applied to cropping systems is not absorbed by plants, but lost to the environment as ammonia (NH
Publisher: Wiley
Date: 18-01-2016
DOI: 10.1111/PCE.12671
Abstract: Nitrogen (N) and potassium (K) are the two most abundantly acquired mineral elements by plants, and their acquisition pathways interact in complex ways. Here, we review pivotal interactions with respect to root acquisition, storage, translocation and metabolism, between the K
Publisher: Wiley
Date: 14-07-2018
DOI: 10.1111/NPH.15343
Abstract: Contents Summary 67 I. Introduction 68 II. Silicon transport in plants: to absorb or not to absorb 69 III. The role of silicon in plants: not just a matter of semantics 71 IV. Silicon and biotic stress: beyond mechanical barriers and defense priming 76 V. Silicon and abiotic stress: a proliferation of proposed mechanisms 78 VI. The apoplastic obstruction hypothesis: a working model 79 VII. Perspectives and conclusions 80 Acknowledgements 81 References 81 SUMMARY: Silicon (Si) is not classified as an essential plant nutrient, and yet numerous reports have shown its beneficial effects in a variety of species and environmental circumstances. This has created much confusion in the scientific community with respect to its biological roles. Here, we link molecular and phenotypic data to better classify Si transport, and critically summarize the current state of understanding of the roles of Si in higher plants. We argue that much of the empirical evidence, in particular that derived from recent functional genomics, is at odds with many of the mechanistic assertions surrounding Si's role. In essence, these data do not support reports that Si affects a wide range of molecular-genetic, biochemical and physiological processes. A major reinterpretation of Si's role is therefore needed, which is critical to guide future studies and inform agricultural practice. We propose a working model, which we term the 'apoplastic obstruction hypothesis', which attempts to unify the various observations on Si's beneficial influences on plant growth and yield. This model argues for a fundamental role of Si as an extracellular prophylactic agent against biotic and abiotic stresses (as opposed to an active cellular agent), with important cascading effects on plant form and function.
Publisher: Springer Science and Business Media LLC
Date: 29-11-2018
DOI: 10.1007/S00425-018-3059-7
Abstract: A systematic analysis of NaCl-dependent, plasma-membrane depolarization (∆∆Ψ) in rice roots calls into question the current leading model of rapid membrane cycling of Na
Publisher: Canadian Science Publishing
Date: 08-2014
DOI: 10.4141/CJPS2013-143
Abstract: Britto, D. T., Balkos, K. D., Becker, A., Coskun, D., Huynh, W. Q. and Kronzucker, H. J. 2014. Potassium and nitrogen poising: Physiological changes and biomass gains in rice and barley. Can. J. Plant Sci. 94: 1085–1089. Soil nitrogen, potassium, and water are three of the most important factors influencing, often interdependently, the growth of plants. Maximizing plant growth is not simply a matter of maximizing the availability of these and other nutrients indeed, excess supply can be deleterious to plant performance. Rather, optimal performance may come about by adjusting the supply of each of the disparate factors required for plant growth, not only in idually, but in relation to one another. In our work investigating the nutritional maximization of plant growth, we have found that altering the ratios of N and K provided to seedlings of cereal grasses can result in very substantial increases in vegetative biomass accrual, e.g., % of low-K + controls, in short-term studies with rice, the world's most important cereal grain, and even greater gains in grain yield, in the longer term. Hence, the findings in our laboratory are of direct relevance to the aim of NSERC's Green Crop Network, which was to contribute to the amelioration of climate change by improvement of carbon capture and sequestration in crop plants. In addition, these findings may help to increase the world's food supply, the security of which is sometimes at odds with proposed means to thwart climate change. Our work in this area has also led to a potential breakthrough of a more fundamental sort in plant nutritional biology, which may in itself have important practical implications: evidence that aquaporin-type transport proteins conduct rapid NH 3 fluxes into roots at toxic levels of external ammonia/ammonium.
Publisher: Wiley
Date: 28-01-2010
DOI: 10.1111/J.1469-8137.2009.03169.X
Abstract: *Stimulation of potassium (K(+)) efflux by sodium (Na(+)) has been the subject of much recent attention, and its mechanism has been attributed to the activities of specific classes of ion channels. *The short-lived radiotracer (42)K(+) was used to test this attribution, via unidirectional K(+)-flux analysis at the root plasma membrane of intact barley (Hordeum vulgare), in response to NaCl, KCl, NH(4)Cl and mannitol, and to channel inhibitors. *Unidirectional K(+) efflux was strongly stimulated by NaCl, and K(+) influx strongly suppressed. Both effects were ameliorated by elevated calcium (Ca(2+)). As well, K(+) efflux was strongly stimulated by KCl, NH(4)Cl and mannitol , and NaCl also stimulated (13)NH(4)(+) efflux. The Na(+)-stimulated K(+) efflux was insensitive to cesium (Cs(+)) and pH 4.2, weakly sensitive to the K(+)-channel blocker tetraethylammonium (TEA(+)) and quinine, and moderately sensitive to zinc (Zn(2+)) and lanthanum (La(3+)). *We conclude that the stimulated efflux is: specific neither to Na(+) as effector nor K(+) as target composed of fluxes from both cytosol and vacuole mediated neither by outwardly-rectifying K(+) channels nor nonselective cation channels attributable, alternatively, to membrane disintegration brought about by ionic and osmotic components of limited long-term significance, unlike the suppression of K(+) influx by Na(+), which is a greater threat to K(+) homeostasis under salt stress.
Publisher: Elsevier BV
Date: 08-2020
Publisher: Wiley
Date: 14-07-2015
Publisher: Oxford University Press (OUP)
Date: 11-01-2018
DOI: 10.1093/JXB/ERX460
Publisher: Wiley
Date: 20-08-2010
DOI: 10.1111/J.1469-8137.2010.03436.X
Abstract: Potassium (K(+) ) flux into plant cells is a well-characterized ion transport phenomenon. By contrast, little is known about the mechanisms and regulation of K(+) flux from the cell. Here, we present a radioisotopic analysis of K(+) fluxes from roots of intact barley (Hordeum vulgare), in the context of recent discoveries in the molecular biology and electrophysiology of this process. Plants were labelled with (42)K(+), and kinetics of its release from roots were monitored at low (0.1 mM) or high (1.0 mM) external K concentration, [K(+)](ext), and with the application of channel modulators and nutrient shifts. At 0.1 (but not 1.0) mM [K(+)], where K(+) efflux is thought to be mediated by K(+)-outward-rectifying channels, (42)K(+) efflux was inhibited by the channel blockers barium (Ba(2+)), caesium (Cs(+)), tetraethylammonium (TEA(+)), and lanthanum (La(3+)). Ammonium and nitrate (10 mM) stimulated and inhibited (42)K(+) efflux, respectively, while 10 mM [K(+)](ext) or [Rb(+) ](ext) decreased it. No evidence for the involvement of ATP-binding cassettes, nonselective cation channels, or active K(+)-efflux pumps was found. Our study provides new evidence for the thermodynamic transition between high- and low-affinity transport, from the efflux perspective, identifying the operation of channels at low [K(+)], and the cessation of transmembrane efflux at high [K(+)].
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.TPLANTS.2017.05.004
Abstract: Although the global nitrogen (N) cycle is largely driven by soil microbes, plant root exudates can profoundly modify soil microbial communities and influence their N transformations. A detailed understanding is now beginning to emerge regarding the control that root exudates exert over two major soil N processes - nitrification and N
Publisher: Wiley
Date: 20-03-2014
DOI: 10.1111/PPL.12174
Abstract: K(+) channels are among the best-characterized classes of membrane protein in plants. Nevertheless, in-planta demonstrations of traits emerging from molecular characterizations have often been insufficient or lacking altogether. Such linkages are, however, critical to our basic understanding of plant nutrition and to addressing 'real-world' issues that are faced in environmental and agricultural settings. Here, we cover some of the recent advances in K(+) acquisition with particular focus on voltage-gated K(+) channel functioning and regulation in roots, and highlight where linkages to in-planta behavior have been successfully made and, conversely, where such linkages are yet to be made.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.PLANTSCI.2015.12.003
Abstract: Potassium (K(+)) acquisition in roots is generally described by a two-mechanism model, consisting of a saturable, high-affinity transport system (HATS) operating via H(+)/K(+) symport at low ( 1mM) [K(+)]ext. Radiotracer measurements in the LATS range indicate that the linear rise in influx continues well beyond nutritionally relevant concentrations (>10mM), suggesting K(+) transport may be pushed to extraordinary, and seemingly limitless, capacity. Here, we assess this rise, asking whether LATS measurements faithfully report transmembrane fluxes. Using (42)K(+)-isotope and electrophysiological methods in barley, we show that this flux is part of a K(+)-transport cycle through the apoplast, and masks a genuine plasma-membrane influx that displays Michaelis-Menten kinetics. Rapid apoplastic cycling of K(+) is corroborated by an absence of transmembrane (42)K(+) efflux above 1mM, and by the efflux kinetics of PTS, an apoplastic tracer. A linear apoplastic influx, masking a saturating transmembrane influx, was also found in Arabidopsis mutants lacking the K(+) transporters AtHAK5 and AtAKT1. Our work significantly revises the model of K(+) transport by demonstrating a surprisingly modest upper limit for plasma-membrane influx, and offers insight into sodium transport under salt stress.
Publisher: Wiley
Date: 15-03-2019
DOI: 10.1111/NPH.15764
No related grants have been discovered for Devrim Coskun.