Dynamic ¹³C/¹H NMR imaging uncovers sugar allocation in the living seed

Abstract

SummarySeed growth and accumulation of storage products relies on the delivery of sucrose from the maternal to the filial tissues. The transport route is hidden inside the seed and has never been visualized in vivo. Our approach, based on high-field nuclear magnetic resonance and a custom made

Development of real-time radioisotope imaging systems for plant nutrient uptake studies

“…Several approaches have combined the positron-imaging system with other methods, such as magnetic resonance imaging and X-ray computed tomography [5,6]. However, as long as positron emitters are applied, positron escape from the sample will always remain an issue when they are used with plant samples.…”

Multiscale Metabolic Modeling: Dynamic Flux Balance Analysis on a Whole-Plant Scale

“…In recent years, the FBA approach has been applied to several different plant species, such as maize (Zea mays;Dal'Molin et al, 2010;Saha et al, 2011), barley (Hordeum vulgare;Grafahrend-Belau et al, 2009b;Melkus et al, 2011;Rolletschek et al, 2011), rice (Oryza sativa; Lakshmanan et al, 2013), Arabidopsis (Arabidopsis thaliana; Poolman et al, 2009;de Oliveira Dal'Molin et al, 2010;Radrich et al, 2010;Williams et al, 2010;Mintz-Oron et al, 2012;Cheung et al, 2013), and rapeseed (Brassica napus; Schwender, 2011a, 2011b;Pilalis et al, 2011), as well as algae (Boyle and Morgan, 2009;Cogne et al, 2011;Dal'Molin et al, 2011) and photoautotrophic bacteria (Knoop et al, 2010;Montagud et al, 2010;Boyle and Morgan, 2011). These models have been used to study different aspects of metabolism, including the prediction of optimal metabolic yields and energy efficiencies Boyle and Morgan, 2011), changes in flux under different environmental and genetic backgrounds (Grafahrend-Belau et al, 2009b;Dal'Molin et al, 2010;Melkus et al, 2011), and nonintuitive metabolic pathways that merit subsequent experimental investigations (Poolman et al, 2009;Knoop et al, 2010;Rolletschek et al, 2011). Although FBA of plant metabolic models was shown to be capable of reproducing experimentally determined flux distributions (Williams et al, 2010;Hay and Schwender, 2011b) and generating new insights into metabolic behavior, capacities, and efficiencies (Sweetlove and Ratcliffe, 2011), challenges remain to advance the utility and predictive power of the models.…”

Combined Noninvasive Imaging and Modeling Approaches Reveal Metabolic Compartmentation in the Barley Endosperm

“…The gene Jekyll controls cell differentiation and cell death within the nucellar projection of caryopsis and in so doing also affects Suc release from the pericarp into the endosperm. When Jekyll was downregulated by means of RNA interference, the release rate of Suc was greatly reduced (Melkus et al, 2011). A strong repression of Jekyll (by ;90%) resulted in a switch from cell death to calluslike growth in the nucellar projection, which expanded and eventually replaced the starchy endosperm ( Figure 6A).…”

“…Apart from the transfer cells and aleurone layer, the barley endosperm appears quite homogeneous. However, in vivo tracking during grain filling has established regional variation in the supply of Suc to the endosperm (Melkus et al, 2011), clear developmental gradients (Sabelli and Larkins, 2009), and uneven levels of hypoxia within the caryopsis (Rolletschek et al, 2004). These localized differences in the internal environment of the endosperm suggest a compartmentation of metabolic activity, although this is difficult to detect directly without access to markers for distinct biochemical events.…”

“…Dynamic MRI demonstrates that Suc passes via crease vein and nucellar projection toward the endosperm and spreads centrifugally within endosperm (for more details, see Melkus et al, 2011).…”